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This book must not be 
taken from the Library 

JUN 7 '966 

Barrs Buffvn, 

Buffon's Natural History. 








VOL. X. 




T. Gillet, Printer, Crovrn-CoUTt, Fleet-Street. 







Of the Degeneration of Animals - | 

Nature and Properties of Miucrals, 
Vegetables, &c. 
X^ighty Heat, and Fire - - 27 

Of Air, Water y and Jgarth - - 75 
Experiments on the Progress of Heat in 

Mineral Substances - - - 1C9 
A Table of the Relations of different Mine- 

ral Substances - - - 1S5 

Observations on the Nature of Platina 15(i 
Experiments on Light, and on the 
Heat it can produce. 
Invention of Mirrors to burn at great dis- 
tances - - - - 193 
Observations and Experiments on Trees 

and other Vegetables - - 245 

On the Temperature of the Planets - 279 

General Views of Nature. 
First View - - - S25 

Second View - - - 343 





npHE deer-kind whose horns arc a sort Of 
wood, and of a solid texture, although ru- 
minating, and internally formed like those 
whose horns arc hollow and porous, seem to 
form a separate family, in which the elk is the 
trunk, and therein-deer, stag, axis, fallow-deer, 
and roe-buck, are the lesser and collateral 
branches ; for there are only six species of ani- 
mals whose heads are armed with branched 
horns that fall off and are renewed every j'ear. 
Independently of this generic character, they 
resemble each other still more in formation and 
natural habitude ; we should, therefore, sooner 
expect mules from thestagor fallow-deer, join- 
ed with the rein-deer or the axis, than from a 
union of the stag with the cow 

Wc mio]jtbe still belter authorised to resrard 
all the different kinds of sheep and goats as 
composing but one- family, since ihey produce 
VOL. X. B together 


together mules, "wliich imracdiatelj, and iil 
the first generation, ascend to the species of 
sheep. We might even add to tli is numerous 
family of sheep and goats those of the gazelles 
and bubalus, which are not less in number. 
The mufion, the wild goat, the chamois, the 
antelope, the bubalus, the condoraa, &c. seem 
to be the principal trunks of this genus, which 
contains more than thirty different species, and 
the others are only accessary branches which 
have retained the principal characters of the 
stocks from which they issued ; but which, at 
the same time, have prodigiously varied by 
the influence of the climate, the difference of 
the food, and by the state of slavery to which 
man has reduced most animals. 

The dog, the wolf, the fox, the jackal, and 
Iheisatis, form another genus, the different spe- 
cies of which resemble each other so strongly, 
especially in their internal conformation, and 
in the organs of generation, that it isdiflicult 
to conceive why they do not intermix. From 
the experiments which I made to form a union 
of the dog with the wolf and fox, the repug- 
nance to copulate seemed to proceed from the 
wolf and fox rather than from the dog, that is, 
from the wild animal and not from the tame ; 
for those bitches which I put to the trial would 
readily have permitted the >volfand fox, where- 


as the females of the two latter would never 
suffer the approaches of the dog. The domes- 
tic state seems to render animals less faithful to 
their species : It gives tliem also a greater de- 
gree of heat and fecundity, for the bitcli gener- 
ally produces twice a year, while the females 
of the wolf and fox litter only once ; and it 
is to be presumed, that those dogs which have 
been left in desert countries, and which have 
so greatly multiplied in the island of JaanFer- 
nandes, and in the mountains of St. Domingo, 
&:c. produce only once a year, like the wolfand 
ihe fox. This circumstance, if it were proved 
to be the fact, would fully establish the unit^' 
of genus in these three animals, which resem/- 
ble each other in conformation so strongly as 
to oblige us to attribute their repugnance to 
some external circumstances. 

The dog seems to be (he intermediate spe- 
cies between the fox and the wolf. The an- 
cients have stated 5 that the dog, in some coun- 
tries, and under particular circumstances, en- 
genders with the wolfand fox. I was desir- 
ous of verifying this assertion, and although I 
did not succeed in the trials I made, yet we 
must not conclude thai it is impossible^ for 
ray experiments were with captive animals ; 
and it is know n that in some species captivity 
alone is sufficient to extingnish desire, and tp 



give tliem a repugnance to copulation, even 
viith their own kind ; consequently thej would ^ 
still more refuse to unite with individuals of 
another species: but I am persuaded, that 
"when in a state of freedom, and deprived of 
his own female, the dog would unite with the 
■wolf and fox, particularly if he had become 
■wild, lost his domestic cast, and approached 
the manner andnaturalliabits of these animals. 
The fox and wolf, however, never unite, though 
they live in the same climate and country, but 
support their species pure and unmixed ; we 
must, therefore, suppose a more ancient de- 
generation than history has recorded, if they 
ever belonged to one species ; it was for 
this reason I asserted that the dog was an 
intermediate species between the fox and 
wolf; and his species is also common, since 
it can unite with both ; and if any thing 
could shew that they all three originally 
sprang from the same stock, it is this common 
affinity between the dog, the fox, and the wolf, 
and which seems to bring their species nearer 
than all the conformities in their fisrures and 
organization. To reduce the fox and wolf, 
therefore, into one species, we must return to a 
state of nature very ancient indeed; but in 
their present condition, we must look upon 



the wolf and fox as the chief trunks in the irc- 
rtus of the five animals. The dog, the jackal, 
and the isatis, are only lateral branches 
placed betweeji the two first ; the jackal par- 
ticipates of t!ie dog and wolf, and the isatis of 
the jackal and fox. From a great number of 
testimonies it appears that the jackal and the 
dog engender easily together ; and it is ob- 
servable, from the description and history of 
the isatis, that it almost entirely resembles the 
fox in iU form and temperament, that they 
are equally found in cold countries, but that, 
at the same time, it inclines to the jackal in its 
dis])osition, continual barking, clamorous 
voice, and the habit of always going in packs. 
The shepherd's dog, which I have considered 
as the original stock of every other dog, is, at 
the same time, that which approaches nearest 
in figure to the fox. lie is of the same size, 
and, like the fox, he has erect ears, a pointed 
muzzle, and a strait trailing tail. Re also ap- 
proaches the fox in voice, sagacity, and in- 
stinct. The dog, therefore, may orirrinally 
Jiave been the issue of tlie fox, if not in a di- 
rect, at least in a collateral line. The doir, 
which Aristotle calls canis-lacomct/s, and 
which he affirms to have proceeded from an 
union of the fox and dog, might, possibly, be 



the same as the shepherd's dog, or, at least, it 
has more relation to him than to any other 
dog. We miglit, therefore, be inclined to 
imagine, tliat the epithet laconicus, left unin- 
terpreted by Aristotle, was only given to thi& 
dog because he was found in Laconia, a pro- 
vince of Greece ; and of wliich Lacediemon 
•was the capital ; but if we attentively consider 
the origin of this laconic dog we shall perceive 
that the breed was not confined to the country 
of Laconia, alone but must have been found in 
every country where there were foxes ; and this 
induces me to presume, that the epithet laco^ 
nicus might possibly have been used by Aris- 
totle in a moral sense, to express the brevity 
and acutencss of his voice, because he did not 
bark lilvc other dogs, but had a shorter and 
shriller note, like that of the fox. Now our 
shepherd's dog is that to which we can justly 
apply this term of laconic^ for of all dogs his 
voice is the sharpest and most rarely employed . 
Bedsides, the characters which Aristotle gives to 
his laconic dog agree with those of the shep- 
herd's dog, and perfectly persuade me they are 
the same. 

The genus of cruel and rapacious animals is 
one of the most numerous and most diversified ; 
evils here, as in other cases, seem to be pro- 


NATURAL histohy. 7^ 

duced under every shape, and to assume various 
natures ; the lion and the tiger, being detached 
species, rank in the first line ; all the others, as 
tlie panther, the ounce, the leopard, the lynx, 
the caracal, the jaguar, the cougar, the oce- 
lot, the serval, the margai, and the cat, com- 
pose only one cruel family, whose different 
branches are more or less extended and diver- 
sified according to the difference of climate. 
All these animals resemble each other in natu- 
ral dispositions, although they are very differ- 
ent with respect to size and figure. They all 
have sparkling eyes, short muzzles, and sharp, 
crooked, and retractile claws. They are all 
destructive, ferocious, and untameable. The 
eat, which is the last and the least species, al- 
though reduced to slavery, continues its fero- 
city, and is no less perfidious. The wild cat 
bas preserved the character of the family, and 
is as cruel and mischievous as any of his lar- 
gerkindred. They are allequally carnivorous, 
and enemies to other animals. Man, with all 
his art and power, has not been able to annihi- 
late them : fire, steel, poison, pits, and every 
method has been used against them without 
attaining that point. As the individuals are 
very prolific, and the species numerous, the 
efforts of man have been limited to kecj;'»ng 
them at a distance, and confining them in the 


8 buffon's 

deserts, whmcethej never sail v without sprctid- 
ing terror, and makins: great depredations. A 
single tiger issuing from the forest is sufficient 
to alarm a multitude of people, and oblige 
them to take up arms. What then would be 
tlie consequence if these sanguinary animals 
came in numbers, like wolves or jackals, to 
commit their depredations ? Nature has given 
this instinct to timid animals, but fortunately 
denied it to the bold tribes ; they go singly, 
and depend upon their courage and strength 
for their safety andsupj>ort. Aristotle observ- 
ed, and justly remarked, that of all animals 
furnished with talons not any of them are 
sociable, or go together in troops.* This ob-- 
gervation, which was then confined to four or 
live species only, being all that were known 
ill his time, is extended and verified over ten. 
or twelve other sp(*c!es since discovered. Other 
carnivorous animals, such as the wolf, the 
fox^ the dog, the jackal, and the isatis, whose 
claws are straight, go mostly in <roops, and 
are all timid, and even cowardly. 

B}' thus comparing every quadrnped, and 
ranking ciich v/ith its proper genus, we shall 
find, that the two hundred species of which we 


* Nullum animal cui ungues aduncl, gregaiile esse per- 
pcndimus. Arist.. Kist. Anim. Lib. i. Cap. i. 


have given the history, may be reduced to a 
small number of families, or principal sterns^ 
from which it is not impossible all the others 
have derived their origin. 

To place this reduction in a regular raetliod, 
we shall observe that all the animals of the two 
continents, as well as all those peculiar to the 
Old World, may be reduced to fifteen genera, 
and nine solitary species. These genera are, 
first, the whole hoofed genus, properly so 
called, which includes the horse, the zebra, 
and the ass, with all the prolific and barren 
mules. 2. The large cloverw-hoofcd with hol- 
low horns, as the ox and the buffalo, with 
their varieties. 3. The small cloven-hoofed 
animals with hollow horns, such as the sheep, 
the goat, the gazelle, the antelope, and every 
other species which participates of their nature. 
4. The cloven-hoofed wilh solid horns, which 
are shed and renewed every year ; this family 
contains the elk, the rein-deer, the stag, the 
fallow-deer, the axis, and the roe-buck. 5. 
Theambiguous cloven-hoofed, which is com- 
posed of the wild boar, and all the varieties of 
the hog, such as that of Siam, with a hanging 
belly, that of Guinea, with long ears, pointed 
and turned backwards, and that of the Canary 
islands with thick and long tusks, &c. 6. 
VOL. X. C The 

10 buffon's 

The very extensive race of digitated carni- 
vorous animals with crooked and retractile 
cla s, in which we must conipreheadthe pan- 
ther, leopard, guepard, ounce, serval, and cat, 
with all their varieties. 7. The digitated 
carnivorous animals with straight and fixed 
claws, which include the wolf, fox, jackal, 
isatis, and the dog, with all their varieties. 8. 
The digitated carnivorous animals with fixed 
claws, and a pouch under their tails. This 
consists of the hyaena, civet, zibet, badger, &c. 
9. The digitated carnivorous animals with 
long bodies, five toes to each foot, and the great 
toe, or thumb, divided from the rest ; tliis ge- 
nus is composed of the ferret, martin, pole-cat, 
weasel, sable, ichneumon. Sec, 10. The nu- 
merous family of digitated quadrupeds which 
have two Inrge incisive teeth in each jaw, and 
no bristles on their bodies ; this contains the 
hare, rabbit, and e\ery kind of squirrels, dor- 
mice, marmots, and rats. li. The digitated 
quadrnpeds, wh ;se bodies are covered with 
spiny quills, as the porcupine and hedge-hog. 
12. The digitated animals covered with scales, 
as the long and short-tailed raanis, or scaly li- 
zards. 13. The amphibious digitated genus, 
which includes the beaver, otter, musk-rats, 
walrus, and seals. 14, i he tour-handed genus, 



wliich comprehends tlie apes, baboons, mon- 
kies, rnakis, loris, &c. 15. The winged qua- 
drupeds, which includes bats, &c. with all 
their varieties. The Piine detached species are 
the elephant, rhinoceros, hipp.^potanuis, gi- 
raffe, camel, lion, tiger, bear, and mole, ^^ hieh 
are all subject t) a greater or smaller number 
of varieties. 

Of those fifteen genera, and nine delaclied 
species, seven genera and two species are com- 
mon to both continents. The two species are, 
the bear and ihe mole ; and (he seven genera 
are, 1. The great cloven- hooted with hollow 
horns, for the ox is found in America, under 
the form of the bison. 2. The cloven- hoofed, 
with solid horns, for the elk exist-, in Canada, 
under the name of orignal ; the n in-decr, un- 
der that of caribou ; and stag>, lallow-dccr, and 
roc-bucks, are found in all the prv)vinces of 
North America. 3, The digitated carnivorous 
animals with fixed claws ; for ihe wolf and (ok. 
are found in the New World ns well as in the 
Old. 4. The digitaied animals with long 
bodies, as the weasel, martin, and pole-cat, 
are met with in America as well as in Europe. 
5. \yc find also m America, partof the digi- 
tated genus with two large inci.ive teeth in 
each jaw, as the squirrels, marmots, rats, &c. 

6. The 

12 BUFFO n'S 

6. The digitated amphibious genus, as the 
walrus, seal, beaver, and otter, exist in the 
North of the New Continent. 7. The winged 
genus exist also in America, as the bat and 

There remains, therefore, only eight genera, 
and five detached species, which are peculiar to 
the Old Continent. These eight genera are, 
1 . The whole-hoofed, properly so called, for 
neitherthehorse, ass, zebra, nor mule, were met 
with in the New Continent. 2. The small 
cloven-hoofed beasts with hollow horns ; for 
sheep, goats, gazelles, or antelopes existed in 
America. 3. The family of hogs ; for the 
species of wild boar is not to be found in 
America ; and although the pecari, and its va- 
rieties, are related to this family, yet they dif- 
fer in a sufficient number of remarkable cha- 
racters to justify their separation. 4. It is the 
same with carnivorous animals with retractile 
claws ; we do not meet with either the panther, 
leopard, guepard, ounce, or serval, in Ame- 
rica; and although the jaguar, couguar, oce- 
lot, and margai, seem to belong to this family, 
there is not one of these species of the New 
World found in the Old, nor one of the Old to 
be met with in the New. 5. The same re- 
niark may be applied to the digitated qua- 


drupeds whose bodies are covered with prickles; 
for although the coendou and the urson ap- 
proach very nigh to this genus, nevertheless, 
these species are very different from those of 
the porcupine and hedge-hog. 6. The digi- 
tated carnivorous genus "with fixed claws, and 
a pouch under the tail; for the hyaena, civets, 
and the badger, do not exist in America. 
7. The four-lianded genus; for neither apes, 
baboons, monkeys, nor makis, have ever been 
seen in America. The sapajous, sagons, opos- 
sums, &c. although quadrumanous, yet they 
essentially differ from those of the Old Conti- 
nent. S. The digitated genus whose bodies are 
covered with scales ; for none of the scaly 
lizards are found in America, and the ant- 
eaters, to wliom they may be compared, arc 
covered with hair, and differ too much from 
the scaly lizards to be considered of the same 

Of the nine detached species, seven, namely, 
the elephant, rhinoceros, hippopotamus, gi- 
raffe, camel, lion, and tiger, are found only in 
the Old World ; and two, viz. the bear and 
mole, are common to both continents. 

If we, in tlie same manner, enumerate the 
animals which are peculiar to the New World, 
we shall find, that there are about fifteen dif- 

14 buffon's 

fcrent species which may be reduced to ten 
genera and four detached species. These four 
species are the tapir, tlie cabiai, the lama, and 
the pecari ; but there is ouly the tapir we can 
absolutely term detached; for the pecari has 
varieties ; and the pacos may be united to the 
lama, and the Guinea hog to the cabiai. The 
ten genera are, 1. Eight ] ecies of sapajous. 
2. Six species of sagoii)s. 3. The opossums, 
phalangers, tarsiers, &c. 4. The jaguars, coii- 
guars, ocelots, raargais, &c. 5. Three or four 
species of coatis. 6. Four or five species of 
mouffetles. 7. The agouti genus, which com- 
prehends the acouchi, the paca, the aperea, 
and the tapeti. 8. That of the armadillos, 
which consists of seven or eight species. 9. 
Two or three species of ant-eaters; and, 
ICthly, The sloth, of which we are acquainted 
with but two species. 

Now these ten genera, and four detached 
species, to which the fifty species of animals 
peculiar to the New World may be reduced, 
though they differ from those of the Old Con- 
tinent, nevertheless have some relations which 
seem to indicate some common afiinity in their 
formation, and lead us to causes of degenera- 
tion, more ancient than any of the rest. We 
have already made the general remark, that all 



animals of the New World were miicli smaller 
than (hose of the Old. This great diniinufiofi 
in size, whatever maybe the cause, is a primary 
kind of dc>generation, which could not be made 
without having a great influence on the figure 
of the animal, and we must not lose sight of 
this effect in comparing them together. 

The largest is the tapir, which though not 
bigger than the ass, can only be compared 
with the elephant, rhinoceros, and hippopota- 
mus ; he claims the first place for size in the 
New Continent, as the elephant does in the 
Old. Like t!ie rhinoceros, his upper lip is 
muscular and projecting; and, like the hip- 
popotamus, he often enters the water. Insome 
respects he represents them all three, and his 
figure, which partakes more of the ass than of 
any other animal, seems to be as degraded as 
his stature is dimini^hed. The horse, the ass, 
the zebra, the elephant, the rhinoceros, and the 
hippopotamus, had no existence in America; 
neither was there an animal in this New Con- 
tinent which could be compared with ihem^ 
fiiiher with respect to size or figure. The ta- 
pir appears (o have some affinity to the whale, 
but he is so mixer!, and approaches so Utile to 
any one of them," that it is not possible to at- 
tribute his origin to the degradation of any par- 

15 buffon's 

ticular species. And, notwitlislanding these 
trifling relations Avhich he is found to have 
"with the rhinoceros, the hippopotamus, and 
Ihe ass, v/e must look on him not only as a pe- 
culiar species, but even as a single genus. 

The tapir, therefore, does not belong to any 
species of the Old Continent, and scarcely 
does hebear any characters which approximate 
him to those animals with which we have just 
been comparing him. The nature of the ca- 
biai is likewise averse from our comparison : 
externally he has no resemblance with any 
other animal, and only approaches the Indian 
hog of the same continent, by his internal 
parts, and both species are absolutely diii'erent 
from all those of the Old Continent. 

The lama and the pacos appear to have more 
significant marks of their ancient parents: the 
first Avith ihe camel, and the second in the 
sheep. The lama, like the camel, has a long 
neck and legs, slender head, and the upper lip 
divided. He resembles the latter also by 
his gentle manners, servility of disposition, 
endurance of thirst, and aptness for labour. 
This was the first and most useful domestic 
animal of the Americans : they made use of 
him to carry burdens, in tlie same manner as 
the Arabs do the camel. Here therefore arc 



sufficient resemblances in the nature of these 
animals, to \\hich we can jet add the perma- 
nent marks of labour ; for though the back of 
the lama is not deformed by hunches like that 
of the camel, he, nevertheless, has callosities 
on liis breast, occasioned by the like habit he 
is used to of resting on that part of his body. 
Yet, notwithstanding all these affinities, the 
lama is a very distinct and different species 
from the camel. He is much smaller, not ex- 
ceeding a fourth or a third part of the camel's 
magnitude. The shape of his body, and the 
quality and colour of his hair, are also very 
different. His temperament is still more so ; 
for he is a phlegmatic animal, and delights 
only to live on the mountains, whereas the 
camel is of a dry temperament, and willingly 
inhabits the most scorching sands. On the 
whole, there are more specific differences be- 
tween the camel and the lama, than between 
the camel and the giraffe. These three ani- 
mals have many characters in common, by 
which they might be referred to one genus,but5 
at the same time, they differ so much in other 
respects,that we cannot suppose them to be the 
issue of one another; they are, therefore, only 
neighbours and not relations. The height of 
the giraffe is nearly double that of the camel, 

VOL. X. D ^(J 

18 buffon's 

and the camel double that of the lama. The 
two first belong to the Old Continent, and form 
separate species. The lama, therefore, which 
is only found in the New, must be a distinct 
species from both. 

It is not the same with respect to the pecari, 
for though a diflferent species from the hog, 
he, nevertheless, belongs to the same genus. 
He resembles the hog in shape, and every ex- 
ternal appearance, and only differs from it in 
some trifling characters, such as the aperture 
on his back, shape of the stomach, intestines, 
&c. We might, therefore, be led to suppose 
that this animal sprung from the same stock 
as the hog, and that he formerly passed from 
the Old World to the New, where, by the 
influence of the soil, he had degenerated to so 
great a degree as now to constitute a distinct 

With regard to the pacos, though it appears 
to have some aflinities with the sheep, in its 
wool and habit of body, yet it differs so great- 
ly in every other respect, that this species 
cannot be looked on either as neighbours or 
allies. The pacos is rather a small lama, and 
has not a single mark Avhich indicates its 
Laving passed from one continent to the other. 
Thus of the four detached species peculiar to 
w the 


the New World, three, namely, the tapir, the 
cabiai, and the lama, with the pacos, appear 
to belong originally to this continent, whereas 
the pecari, which forms the fourth, seems to 
be only a degenerated species of the hog, 
and to have formerly derived its origin from 
the Old Continent. 

By examining and comparing, in the same 
manner, the ten genera, to which we have 
reduced the other animals peculiar to South 
America, we shall discover, not only singular 
relations in their nature, but marks of their 
ancient origin and degeneration. The sapajous 
and sagoins bear so great a resemblance to the 
monkeys, that they are commonly included 
under that name. We have proved, however, 
tliat their species, and even their genera, are 
different. Besides, it would be very difficult 
to conceive how the monkeys of the Old Con- 
tinent could assume in America a difierent- 
shaped visage, a long, muscular, and prehensile 
tail, a large partition between the nostrils, and 
other characters, both specific and generic, hy 
which we have distinguished and separated 
them from the sapajous. But as the monkeys, 
apes, and baboons, are only found in the Old 
Continent, we must look upon the~ sapajous 
and sagoins as their representatives in the New, 


so buffon's 

for these animals have nearly the same form, 
as well externally as internally, and also have 
many things in common in their natural habits 
and dispositions. It is the same with respect to 
the raakis, none of which are found in Ame- 
rica, yet they seem to be represented there by 
the opossums, or four-handed animals, with 
pointed muzzles, which are found in great 
numbers in the New Continent, but exist not 
in the Old. We must, however, observe, that 
there is much more difference between the 
nature and the form of the makis, and of these 
four-handed American animals, than between 
the monkeys and the sapajous ; and that there 
is so great a distance between the opossums and 
the maki that we cannot form an idea that the 
one ever proceeded from the other, without sup- 
posing that degeneration can produce effects 
equal to those of a new nature ; for the greatest 
number of these American four-handed ani- 
mals have a pouch under the belly, ten incisive 
teeth in each jaw, and a prehensile tail ; whereas 
the maki has a flaccid tail, no pouch under the 
belly, and only four incisive teeth in the upper 
jaw, and six in the lower ; therefore, though 
all these animals have hands and fingers of the 
same form, and also resemble each other in the 
elongation of the muzzle, yet their species, 



and even their genera, are so different, that we 
cannot imagine them to be one and the same 
issue, or that such great and general disparities 
have ever been produced by degeneration. 

On the other hand, the tigers of America, 
which we have indicated by the names of ja- 
guars, couguars, ocelots, and margais, though 
different in species from the panther, leopard, 
ounce, guepard, and serval, of the Old Con- 
tinent, are, nevertheless, of the same genera. 
All these animals greatly resemble each other, 
both externally and internally ; they have 
alsothe samenatural dispositions, the same fe- 
rocity, the same vehement thirst for blood, and 
what approximates them still nearer in genus, 
those which belong tothe same continent differ 
more from each other than from those of the 
other Continent. For instance, the African 
panther differs less from the Brasilian jaguar 
than the latter does from the couguar, though 
they are natives of the same country. The 
Asiatic serval, and tlic margai of Guiana, like- 
wise differ less from one another than from th« 
species peculiar to their own continents. We, 
therefore, may justly suppose, that these ani- 
mals had one common origin, and that, havino- 
formerlypassed from one continent to the other, 
their present differences have proceeded only 


22 buffon's 

from the long influence of their new situation. 
The mouffcttes, or stinkards, of America, and 
the i;olecat cf Europe, seem to be of the same 
genus. In general, when a genus is common 
to both continents the species which compose 
it are more numerous in the Old than in the 
New ; but in this instance it is quite the re- 
verse, for there are four or live kinds of pole- 
cats in America, while we have only one, the 
nature of which is inferior to that of all the 
rest ; so that the New World, in its turn, seems 
to have representatives in the Old ; and if we 
judged only from the fact, we might think these 
animals had taken the opposite road, and pas- 
sed from America to Europe. It is the same 
with respect to some other species. The roe- 
bucks and the fallow-deer, as well as the stink- 
ards, are more numerous, larger, and stronger 
in the New Continent than in the Old ; ^^e 
might, therefore, imagine them to be original- 
ly natives of America ; but as we cannot doubt 
that every animal was created in the Old Con- 
tinent, we must, consequently, admit of their 
migration from the Old to the New World, 
and at the same time suppose, that instead of 
having degenerated, like other animals, they 
have improved their original nature by the in- 
fluence of the soil and climate. 



The ant-eaters, wliicli are sini^ular animals, 
and of wliich there are three or four species in 
the New World, seem also to have their repre- 
sentatives in the Old. The scaly lizards re- 
semble them in the pecnliar character of hav- 
ing no teeth, and of being obliged to put out 
their tongues and feed upon ants ; but if we 
would suppose them to have one common ori- 
gin, it is strange, that instead of scales, with 
which they are covered in Asia, they are cloth- 
ed with hair in America. 

With respect to the agoutis, pacos, and other 
animals of the seventh genus peculiar to the 
New Continent, we can only compare them 
with the hare and rabbit, from which, how- 
ever, they all differ in species. What renders 
their being of a common origin doubtful is, 
the hare being dispersed almost over every 
climate of the Old Continent, without having 
imdergone any other alteration than in the co- 
Jour of its hair. We cannot, Avith any founda- 
tion, therefore, imagine that the climate of 
America has so far changed the nature of our 
hares to so great a degree as to make them ta- 
petis or apereas, which have no tail ; or agbutis 
with pointed muzzles, and short round ears; 
or pacos, with a large head, short ears, and u 
coarse hair marked with white stripes. 


S4 kuffon's 

On the whole, the coatis, the armadillos, 
and the sloths, are so different, not only in 
species, but also in genus, from every animal 
of the Old World, that we cannot compare 
them with any one ; it is also impossible to re- 
fer them to any common origin, or attribute to 
the effects of degeneration the prodigious dif- 
ferences found in their nature from that of 
every other animal. 

Thus, of ten genera, and four detached 
species, to which we have endeavoured to re- 
duce all the animals peculiar to the New 
World, there are only two, the genus of the 
jiguars, ocelots, &c. and the species of the 
pecari, with their varieties, which can with any 
foundation be connected with the animals of 
the Old Continent. The jaguars and ocelots 
may be regarded as a species of the leopard or 
panther, and tlie pecari as a species of hog. 
After these are five genera and one detached 
species, namely the species of the lama, and the 
genera of sapajous, sagoins, stinkards, agoutis, 
and ant-eaters,which may becompared,though 
in a very distant and equivocal manner, with 
the camel, monkey, polecat, hare, and scaly 
lizards. There then remain four genera and 
t^o detached species, namely, the opossums, 
the coatis, the armadillos, the sloths, the tapir, 


. •«* « Wk» 


and the cabiai, wliich can neither be referred 
nor compared to any grnera or species of the 
Old Co iinent. This sutficien'ly proves that 
the origin of these animals, peculiar to the 
New world, cannot be attributed merely to 
degeneration. However, great and powerful 
the effects of degeneration may be supposed, 
we cannot, with any appearance of reason, 
persuade ourselves that these animals were 
originally the same as fhose of the Old Conti- 
nent. It is more reasonable to imagine that 
the two continents were formerly joined, and 
that those species which inhabited the New 
World, because they found the climate and 
soil most suitable to their nature, were sepa- 
rated from the rest by the irruption of the sea 
when it divided Asia from Ame» ica . This is a 
tiatural cause, and similar ones might be con- 
ceived which \\ould produce the same e^cct ; 
for example, if the sea should make an irrup- 
tion from the eastern to the w<?stem ssde of 
Asia, and thus separate the southern par's of 
Africa nnd Asia from the res? of the Continent, 
all the animals peculiar to the southern coun- 
tries, such as the elephant, the iJiinoceros, 
the giraffe, the zebra, the crang-uu'ang, &c. 
would be, relatively lo tlioollicrs, the same as 
those of South America at present are; they 
VOL, X. E would 

2(5 BUFFO n's 

would be entirely separated from the animals 
oft lie temperate countries, and could not be 
referred to an origin common to any of the 
species or genera which inhabit these coun- 
tries, on the sole foundation that some imper- 
fect resemblances, or distant relations, might 
be observed between them. 

We must, therefore, to find out the origin 
of these animals, turn back to the time when 
the two continents were not separated, and re- 
fer to the first changes which happened on 
the surface of the globe. We must, at the 
same time, place before our view the two hun- 
dred species of quadrupeds as constituting 
thirty-eight families; and although this is not 
the state of nature, sucli as it is come down to 
us, and as we have represented it, but, on the 
contrary, a much more ancient state, which we 
can only attain by inductions and relations 
nearly as fugitive as time, which seems to 
have effaced their traces, we Iiave endeavour- 
ed, by facts and monuments still existing, to 
return to those first ages of nature, and to 
exhibit those cpochas which appear to be 
jiaobt clearly indicated. 






'^LL the powers of Nature with which we 
are acquainted, may be reduced to two pri- 
mitive forces; the one which causes weight, 
and that which produces heat. The force of 
impulsion is subordinate to thera ; it depends 
on the first for its particular, and on the latter 
•for its general effects. As impulsion cannot 
exercise itself but by tlie means of a spring, 
and the spring only acls by virtue of the force 
which approximates the remote parts, it is 
clear, that to perform its power it has need of 
the concurrence of attraction : for if matter 
ceased to attract, if bodies lost their coherence, 
every spring would be destroyed, every motion 
intercepted, and every impulsion void ; since 
motion ca mot transmit itself from one body to 
another but by elasticity , it is demonstrable, 
that one body absolutely hard and inflexible, 


is buffon's 

would be absolutely immoveable, and entirely 
incapable of receiving Ibe action of another. 
Attraction being a general and permanent ef- 
fect, impulsion, which in most bodies is neither 
constant nor fixed, depends on it as a particular 
effect; for, if all impulsion were destroyed, 
attraction would still equally subsist and act ; 
it is, therefore, this essential difference which 
makes impulsion subordinate to attraction in 
all inanimate and purely passive matter. 

But this impulsion depends still more imme- 
diately, and generally, on the power which pro- 
duces heat ; for it is principally by the means 
of heat, that impulsion penel rates organized 
bodies ; it is by heat that they are formed, 
grow, and develope themselves. We may re- 
fer to attraction alone all the effects of inani- 
mate matter ; and in this same power of attrac- 
tion, joined to that of heat, every phenomena 
of live matter. By live matter I understand 
not only every thing that lives, or vegetates, 
but also every living organic molecule, dis- 
persed in the waste or remains of organized 
bodies. In it I comprehend also light, heat, 
fire, and all matter which appears to be active 
in itself. Now this live matter always tends 
from the ceritre to the circumference, whereas 
brute or inanimate matter tends from the cir- 


cumference to (he centre. It is an expansive 
power which animates the live matier, and it 
is an attractive force to which the inanimate 
matter is obedient. Al hough the directions 
of these two powers be diametrically opposite, 
yet they balance themselves withoui ever Mng 
destroyed, and from the combination of these 
two powers equally active, all the phenomena 
of the universe result. 

But it may be said, by reducing all the powers 
ofNature to attraction and expansion, without 
giving the cause of either, and by rendering 
impulsion, (which is the only force whose cause 
is known and demonstrated to our senses) su- 
bordinate to both, do you not abandon a clear 
idea, and substitute two obscure hypotheses ia 
its place ? To this I answer, that as we know 
nothing except by comparison, v.e shall never 
have an idea of what general effect will pro- 
duce, because such an effect belonging to 
every thing, we should be unal^le to compare 
it to any, and consequently there is no hope 
of ever knowing the cause or reason why all 
matter attracts, although we are sensible sook 
is the fact. If, on the contrary, the eflfect were 
particular, like that of the atlraclion of the 
loadstone and steel, we might es'pect to disco- 
ver the cause, because it might be compared 
to other particalar effects. To ask wliy matter 


so uuffon's 

is extended, heavy, and impenetrable, are ill* 
conceived propositions, and merit not an an- 
sweip; it is the same with respect to every 
particular properly, when it is essential to the 
subject, and we might as well be interrogated 
wliy red is red ? The philosopher becomce a 
child when he puts such questions ; and how- 
ever much they may be forgiven to the last, 
the former ought to exclude them from his 

It is sufilcient that the forces of attraction 
and expansion are two general, real, and fixed 
effects, for us to receive them for causes of par- 
ticular ones; and impulsion is one of these ef- 
fects, which we must notlook upon as a general 
cause, known and demonstrated by our senses, 
since we have proved that this force of impul- 
sion cannot exist nor aci, but by the means of 
attraction, which docs not fall upon our senses. 
Nothing is more evident, nay, certain, than 
the communication of motion by impulsion ; 
it is sufficient for one body to strike another to 
produce this efiect. But even in this sense, is 
not the cause of attraction most evident, and 
that motion, in all cases, belongs more to at- 
traction than impulsion ? 

The first reduction being made, it might 
perhaps be possible to adduce a second, and 
to bring buck the power even of expansion to 



that of attraction, iasomuch that all the forces 
of matter would depend solely on a primilive 
one ; at least this idea seems to be worthy of 
that sublime simplicity with which nature 
works. Now cannot we conceive that tliis 
attraction changes into repulsion every time 
that bodies approach near enough to rub to- 
gether, or strike one against the other ? Ira- 
penetrability, which we must not regard as a 
force, but as a resistance essenlial to matter, 
not permitting two bodies to occupy the same 
place, what must happen when tw o molecules, 
which attract the more powerfully as they ap- 
proach nearer, suddenly strike against each 
other ? Does not then this invincible resistance 
of impenetrability, become an active force, 
which, in the contact, drives the bodies with 
as much velocity, as they liad acquired at the 
moment they touched ? And from hence the 
expansive force will not be a particular force 
opposed to the attractive one, but an effect 
derived therefrom. I own, that we must sup- 
pose a perfect spring in every molecule, and 
in every atom of matter, to have a clear con- 
ception hoAv this change of attraction into re- 
pulsion is performed. But even this is suffi- 
ciently indicated by facts; the more matter is 
attenuated, the more it takes a spring. Earth 
and water, which are the most gross aggregates, 
have a less spring than air; and fire, which is 



the most subtle of all the elements, is also that 
■which has the most expai»sive force. The 
smallest molecules of matter, the smallest atoms 
with which we are acquainted are those of 
light, and we are sensible of their being perfectly 
elastic, since the angle nnder which the light is 
reflected, is always equal to that under which it 
comes. We may thc^refore ii fer, that all the con- 
stitutive parts of matter in eneral, are a perfect 
spring; and that thisspring produces all the ef* 
fects of the expansive force, every time that bo- 
dies strike by meeting in op^x>site directions. 

We know of no other mcnns of producing 
fire, but by striking or rubbing bodies toge- 
ther*; since hy supposing man without any 
burning glasses, and without actual fire, he 
will have no other meacis of producing it; 
for the fire produced by uniting the rays of 
light, or by application of tire already pro- 
duced, hud tl'e same origin* 

Expansive force, therefore, in reality might 
be only the re-action of the attractive, a re- 
action which operates every time that the pri- 
mitive molecules of matter, always attracted 
Dne by the other, happen immediately to 
touch ; for then it is necessary, that they be 


* The fire, which arises fi-om the fermentation of herbs 
heaped together, and which manifests itself in effervescences, 
is not an exception that can be opposed to me, since th» 
produciion of fire depends, like all the rest, from the action 
©f the ihock of the parts of matter one againBt the other. 


repelled with as much veloeily as they had 
acquired in a contrary direction, at the mo- 
vement of contact ; and when these molecules 
are absolutely free from all coherence and only 
obey the motion alone produced by their at- 
traction, this acquired velocity is immense ia 
the point of contact. Heat, light, and fire, 
which are the greatest effects of expansive 
force, will be produced every time that bodies 
are either artificially or naturally divided into 
very minute parts, and meet in opposite di- 
rections ; and the heat will be so much the 
more sensible, the light so much the more 
bright, the fire so much the more violent, ac- 
cording as the molecules are precipitated one 
against the other with more velocity by their 
force of mutual attraction. 

trom the above it must be concluded, that 
all matter may become light, heat, and fire ; 
and that this matter of fire and light is not a 
substance different from every other, but pre- 
serves all its essential qualities; and even most 
of the attributes of common matter, is evidently 
proved by, first, light, though composed of 
particles almost infinitely minute, is, never- 
theless, still divisible, since with the prism we 
separate the rays, or different coloured atoms 
one from another. Secondly, light, though 
in appearance endowed with a quality quite 
toL. X. F opposite 

54 buffon's 

opposite to that of weiglit, that is, with a vola- 
tility which we might thinkessential, is, never- 
theless, heavy like all matter, since it bends 
every time it passes near other bodies, and 
finds itself inclined to their sphere of attraction . 
It is very heavy, relatively to its volume, 
which is very minute, since the immense velo- 
city with which light moves in a direct line, 
does not prevent it from feeling sufficient at- 
traction near other bodies, for its direction to 
incline and change in a manner very sensible 
to our eyes. Thirdly, the substance of light 
is not more simple than all other matter, since 
it is composed of parts of unequal weight ; the 
red rays are much heavier than the blue ; and 
between these two extremes there are an infinity 
of intermediate rays, which approach more or 
less the weight of the red, or the lightness of 
the blue according to their shades. All these 
consequences are necessarily derived from the 
phenomena of the inflection of light, and of its 
refraction, which, in reality, is only an in- 
flexion which operates when light passes across 
transparent bodies. Fourthly, it may be de- 
monstrated, that light is massive, and that it 
acts, in some cases, as all other bodies act ; 
for, independently of its ordinary efiect, which 
is to shine before our eyes, and by its own 
action, always accompanied with lustre, and 



often with lieat, it acts by its mass when it is 
condensed, and it acts to the point of putting 
in motion heavy bodies placed in the focus of 
a good burning glass : it turns a needle on a 
pivot placed in its focus : it displaces leaves 
of gold or silver before it melts or even sensibly 
heats them. This action, produced by its 
mass, precedes that of heat : it operates be- 
tween the condensed light and the leaves of 
metal in the same manner as it operates between 
two other bodies which become contiguous, 
and, consequently, have still this property in 
common with all other matter. Fifthly, light 
is a mixture, like common matter, not only of 
more gross and minute parts, more or less 
heavy or moveable , but also diflferently shaped . 
Whoever has observed the phenomena which 
Newton calls the access of easy refiection^ and 
of easy transmission of light ; and on the ef-* 
feels of double refraction of rock and Iceland 
chrystal, must have perceived that the atoms 
of light have many sides, many different sur- 
faces, which, according as they present them- 
selves, constantly produce different effects. 

This, therefore, is suflScient to demonstrate 
that light is neither particular nor different 
from common matter; that its essence, and its 
essential properties are the same ; and that it 


S6 buffon's 

differs only from having undergone, in (he 
point of contact, the repulsion whence its vo- 
latility proceeds ; and in the same manner as 
the effect of the force of attraction extends, 
always decreasing as the space augments, the 
effects of repuLion extend and decrease the 
more, but in an inverted order, insomuch that 
YPe can apply to the expansive force all that 
is known of the attractive. These are two 
instruments of the same nature, or rather the 
same instrument, only managed in two oppo- 
site directions. 

AH matter will become light, for if all co- 
herence were destroyed it would be divided into 
molecules suflficiently minute, and these mole- 
cules, being at liberty, will be determined by 
their mutual attraction to rush one against the 
other. In the moment of the shock the re- 
pulsive force will be exercised, the molecules 
will fly in all directions with an almost infinite 
volatility, which, nevertheless, is not equal to 
their velocity acquired in the moment of con- 
tact, for the law of attraction being augmented 
as the space diminishes, it is evident, that at 
the contact the space is always proportionable 
till the square of the distance becomes nil, and, 
consequently, the velocity acquired by virtue 
of the attraction must at this point become 



almost infinite : aj;d it would be perfectly so 
if the contact were immediate, and, conse- 
quently, tlie distance between the two bodies 
void ; but there is nothing in nature entirely 
nil, and nothing truly infinite ; and all that I 
have observed of the infinite minuteness of the 
atoms which constitute light, of their perfect 
spring, and of the nil distance in the moment 
of contact, must be understood only relatively. 
If this metaphysical truth were doubted, a phy- 
sical demonstration may begiven. It is pretty 
generally known that light employs seven mi- 
nutes and a half to come from the sun to the 
earth ; supposing, therefore, the sun at thirty-? 
six millions of miles, light darts through this 
enormous distance in that short space, that is 
(supposing its motion uniform), h 0,000 miles 
in one second. But this velocity, although 
prodigious, is yd far from being infinite, since 
it is determinable by numbers. It will even 
cease to appear so prodigious, when we reflect 
on the celerity of the motion of the comets to 
their perihelia, or even that of the planets, and 
by computing that, we shvall find that the ve- 
locity of those immense masses may pretty 
nearly be compared to that of the atoms of 
So, likewise, as all matter can be converted 


S8 BUFFO n's 

into light by the division and expulsion of its 
parts, when they feel a shook one against 
another, we shall find that all the elements are 
convertible ; and if it have been doubted whe- 
ther light, which appears to be the most simple 
element, may be converted into a solid sub- 
stance, it is because we have not paid sufficient 
attention to every phenomena, and were in- 
fected with the prejudice, that being essentially 
volatile it can never become fixed. But it is 
plain that the fixity and volatility depend oa 
the same attractive force in the first case, and 
become repulsive in the second ; and from 
thence are we led to think that this change of 
matter into light, and from light into matter, 
is one of the most frequent operations of 

Having shewn that impulsion depends on 
attraction ; that the expansive force, like the 
attractive, becomes negative ; that light, heat, 
and fire, are only modes of the common exist- 
ing matter ; in one word, tliat there exists but 
one sole force, and one sole matter, ever ready 
to attract or repel, according to circumstances ; 
let us see how, with this single spring, and 
this siiJgle subject, Nature can vary her works, 
ad infinitum. In a general point of view, 
light, heat, and fire, only make one object, but 


in <i particular point of view they are three 
distinct objects, which, although resembling 
in a great number of properties, differ never- 
theless in a few others, sufficiently essential for 
us to consider them as three distinct things. 

Light, and elementary fire, compose, it is 
said, only one and the same thing. This may 
be, but as we have not yet a clear idea of 
elementary fire we shall desist from pronounc- 
ing on this first point. Light and fire, such as 
we are acquainted with, are two distinct sub- 
stances, differently composed. Fire is, in fact, 
very often luminous, but it sometimes also ex- 
ists without any appearance of light. Fire, 
whether luminous or obscure, never exists 
without a great heat, whereas light often burns 
with a noise without the least sensible heat. 
Light appears to be the work of nature while 
fire is only the produce of the industry of man. 
Light subsists of itself, and is found diffused 
in the immense space of the whole universe. 
Fire cannot subsist without food, and is only 
found in some parts of this space where man 
preserves it, and in some parts of the profundity 
of the earth, where it is also supported by 
suitable food. Light when condensed and 
united by the art of man, may produce fire, 
but it is only as much as it lets fall on com- 

40 ftUFFON's 

bustlble matters. Light is therefore nomorej 
and in this single instance, only the principle 
of fire and notthe fire itself: even this principle 
is not immediate, for it supposes the inter- 
mediate one of heat, and which appears to 
appertain more than light to the essence of fire. 
Now heat exists as often without light as light 
exists without heat : these two principles 
might, therefore, appear not to bind them ne- 
cessarily together ; their effects are not con* 
temporary, since in certain circumstances we 
feel heat long before light appears, and in 
others we see light long before we feel any 
heat. Hence is not heat a mode of being, a 
modification of matter, which, in fact, differs 
less than all the rest from that of light, but 
which can be considered apart, and still more 
easily conceived ? It is, nevertheless, certain, 
that much fewer discoveries have been made 
on the nature of heat than on that of light ; 
whether man better catches what he sees 
than what he feels ; whether light, presenting 
itself generally as a distinct and different sub- 
stance from all the rest, has appeared worthy 
of a particular consideration j whereas heat, the 
effect of which is the most obscure, and pre- 
sents itself as a less detached and less simple 
object, has not been regarded as a distinct 



substance but as an attribute of light and 

Tbe Erst thing worthy of remark, is, that 
the scat of heal is quite different from that of 
Jight : the hitter occupies and runs through 
the void space of the universe ; heat, on the 
contj*ary, is diffused through all solid matter. 
The globe of the earth, and the whole matter 
of which it is composed, have a considerable 
Xlegree of heat. Water has its degree of heat 
which it does no* lose but by losing its fluidity. 
The air has also heat, which we call its tempe- 
rature,and which varies much, but is never ea- 
tirely lost, since its springs subsist even in the 
greatest cold. Fire has also its different degrees 
of heat, which appear to depend less on its own 
;3ature, than on that of the aliments 'vvhich feed 
it. Thus all known matter possesses warmth ; 
and, hence, heat is a much more general affec- 
tion than that of light. 

Heat penetrates every body without excep- 
iion which is ex^^osed to it, while light passes 
through transparent bodies only, and is stop- 
ped and in part repelled, by every opaque one. 
Heat, therefore acts in a much more general and 
palpable manner than light, and although the 
molecules of heal are excessively minute, since 
they penetrate the most compact bodies, it 
voJL, X. G seems 

4$ buffon's 

seems, however, demonstrable, that they arc 
much more gross than those of light ; for we 
make heat with light, by collecting it in a great 
quantity. Besides, heat acting on the sense of 
feeling, it is nececssary that its action be pro- 
portionate to the grossness of this sense, the 
same as the delicacy of the organs of sight ap- • 
pears to be to the extreme fineness of the parts 
of light ; these parts move with the greatest 
velocity, and act in the instant at immense dis- 
tances, whefcas those of heat have but a slow 
progressive motion, and only extend to small 
intervals from thebodies whence they emanate. 
'J'he principle of all heat seems to be the at- 
trition of bodies ; all friction, that is, all con- 
trary motion between solid matters produces 
heat ; and if the same effect do not happen to 
fluids, it is because their parts do not touch 
close enough to rub one against the other ; 
and that, having little adherence between 
them, their resistance to the shock of other 
bodies is too weak for the heat to be produced 
to a sensible degree ; but we often see light 
produced by an attrition of a fluid, without 
feeling any heat. All bodies whether great 
or little become heated as soon as they meet in 
a contrary direction ; heat is, therefore, pro- 
duced by the motion of all palpable matter ; 



^vbile the production of light, which is also 
made by motion, but in a contrary direciion, 
supposes also the division of matter into very 
minute parts: and as this operation of Nature 
is the same with respect to both, we must con- 
clude, that the atoms of light are solid of them- 
selves, and are hot at the moment of their 
birth . But we cannot be equally certain, that 
they preserve their heat in the same degree 
as their light, nor that they cease to be 
hot before they cease to be luminous. 

It is well known, that heat grows less, or 
cold becomes greater, the higher we ascend on 
the mountains. It is true that the heat which 
proceeds from the terrestrial globe, is of course 
sensibly less on those advanced points, than 
it is on the plains ; but this cause is not pro- 
portionable to the effect ; the action of heat, 
which emanates from the terrestrial globe, not 
being able to diminish but by the square of 
the distance, it does not appear that at the 
height of half a mile, which is only the three 
thousandth part of the serai-diameter of tlie 
globe, whose centre must be taken for the fo- 
cus of heat, that this difference, which in this 
supposition is only a unit and nine millions, 
can produce a diminution of heat nearly so 
considerable ; for the thermometer lowers at 



that height, at all time*? of the year, to the 
freezina: point. It is liot probable, that this 
great difFerence of heat himplj proceeds from 
the difFerence of the earth ; dnd of that we 
must be fully convinced, if we consider, that 
at the mouih of the volcanos, where <he earth 
is hott( I than in any other par( oh the surface 
of the globe, the air is nearly as cold as on 
other mountains of the samfe height. 

It may then be supposed that the atonis of 
light, though very hot at the momeilt of quit- 
ting the sun, are greatly cooled during the se- 
ven minutes and a half itl which they pass 
from that body to the earth j and this in fact 
■would be the case if they were detached ; but, 
as they almost immediately succefcd each 
other, and are the more confined as they are 
nearer the place of their origin, the heat lost 
by each atom falU on the neighbouring oiies ; 
and this reciprocal communication supports 
the general heat of light a longer time ; and 
as their constant direction is in divergent rays, 
their distance from each other increases ac- 
cording to the space they run over ; and as 
the heat which flies from each atom, as a cen* 
tre, diminishes also in the same ratio, it fol- 
lows, that the light of the solar raysj decreas- 
ing in an inverted ratio from the square of the 



distance, that of (heir heat decreases in an in- 
verted ratio of the square of the same distance. 
Taking therefore the senii-diametcr of the 
sun for a unif, and supposin*^ the action of 
light to be as 1000 to the distance of a derai- 
diameter of the surface of this planet, it will 
not be more tlian as — — to the distance of 


two demi-diameters : as ^-— to tliat of three 


demi-diameters, hs ^°° to the distance of four 
demi-diameters; and finally, Avhen it atrives 
at us, who are distant from the sun thirty-six 
millions of leagues, that is about two hundred 
and twenty-four of its demi-diameters, the ac* 
tion of liHit will be no more than as ^°"° 

" 5 6 2 5' 

that is, more than 50,00'' times weaker than 
at its issuing from the sun ; and the heat of 
each atom of light being also supposed 1000 
at its issuing from the sun, will not be more 
than as i-^^ 1^^ 1-°^ to the successive of 

15^ 81 256 

Ij ?, 3, demi-diameters, and, when arrived at 
lis as ^ /°°° — that is. more than two 

^ 25628 0O625 ' 

thousand tive hundred millions of times 
weaker than at issuing from the sun. 

If even this diminution of the heat of light 
should not be admitted by reason of the squared 
square of the distance to the sun, it will still 
be evident that heat, in its propagation, dimi- 
nishes more than li^ht. If we excite a very 
strong heat, by kindling a large fire, we shall 


40 buffon's 

only feel it at a moderate distance but tvc shall 
see the light at a very great one. If we bring 
our hands by degrees nearer and nearer a 
body excessively hot, we shall perceive that 
the heat increases much more in proportion 
than as the space diminislies ; for we may 
warm ourselves wilh pleasure at a distance 
whicli differs only by a few inches from that 
at which we should be burnt. Every tiling, 
therefore, appears to indicate, that heat dimi- 
nishes in a greater ratio than light, in propor- 
tion as both are removed from the focus 
lyhence they issued. 

This might lead us to imagine, that the 
atoms of light would be very cold when they 
came to the surface of our atmosphere; but 
that by traversing (he great extent of this 
transparent mass, they receive a new heat by 
friction. The infinite velocity with which 
the particles of light rub against those of the 
air, must produce a heat so much the stronger 
as the friction is more multiplied : and it is, 
probably, for this reason, that the heat of the 
solar rays is found much stronger in tlic lower 
parts of the atmosphere, and that the coldness 
of the air appears to augment as we are ele- 
vated. Perliaps, likewise, as light receives 
heat only by uniting, a great number of atoms 
of light is required to constitute a single atom 



of heat, and this may be the cause why the 
feeble light of the moon, although in the at- 
mosphere, like that of the sun, does not re- 
ceive any sensible degree of heat. If, as M, 
JBouguer says, the intensity of the light of the 
sun to the surface of the earth is S00,000 times 
stronger than that of the moon, the latter must 
be almost insensible, even by uniting it in the 
foous of the most powerful burning glasses, 
which cannot condense it more than 2000 
times ; subtracting the half of which for the 
loss by reflexion or refraction, there remain.s 
only a SOOdth part intensity to the focus of 
the glass. 

Thus, we must not infer that light can exist 
without any heat, but only that the degrees 
of this heat are very different, according io 
different circumstances, and always insensible 
when light is very weak. Heat, on the con- 
trary, seems to exist habitually, and even to 
cause itself to be strongly felt witliout light; 
for in general it is only when it becomes ex- 
cessive, (hat light accompanies it. But the 
very essential difference between these two mo- 
difications of matter is, that heat, which pene- 
trates all bodies, does not appear to fix in any 
one, whereas light incorporates and extin- 
guishes in all those which do not reflect, or 


48 Bt'FFON's 

permit it to pass freely ; Iieat bodies of all kinds 
to any degree, in a very short time they -wili 
lose the acquired heat, and return to the general 
temperature. If we receive light on black or 
white bodies, rude or polished, it will easily be 
perceived, that some admit, and others repel 
it; and that instead of being affected in a uni- 
form manner as they are by heat, they are only 
so relatively to their nature, colour, and po- 
lish. Black will absorb more light than white, 
and the rough more than the smooth. Light 
once absorbed remains fixed in the body which 
received it, nor quifs it like heat; wheace 
we must conclude, that atoms of light may be- 
come constituent parts of bodies by uniting 
with the matter which composes them ; whereas 
heat not fixing at all, seems to prevent the 
union of every part of matter, and only acts to 
keep them separate. Nevertheless, tl^ere are 
instances where heat remains fixed in bodies, 
and others where the light they have absorbed 
re-appears, and goes out like heat. 

After all there appear to be two kinds of 
heat, the one luminous, of which tlie sun is the 
focus; the other obscure, of which the grand" 
reservoir is tlic terrestrial globe. Our body, as 
maliing part of the globe, participates of this 
obscure lieat : and it is for this reason, that 



it IS still obscure to us, because we do not 
perceive it by any one of our senses. It is 
with respect to tbis heat of the globe, as with 
its motion, we are subject ^o and participate 
thereof without feeling or doubting of it z from 
hence it happened that physicians at first car- 
ried all their views and enquiries on the heat 
of the sun, without suspecting that it makes but 
a very small part of what we really feel ; but 
having made instruments to discover the differ- 
ence of the immediate heat of the rays of the 
sun, they with astonishment found that the 
lieat of them was sixty-six times stronger in 
summer than in winter, notwithstanding the 
strongest heat of our summer differs only a 
seventh from the strongest cold of our winter; 
from whence they have concluded, that, inde^ 
pendent of the heat we receive from the sun, 
there emanates another, even from this terres- 
trial globe, which is much more considerable ; 
insomuch, that it is at present demonstrable, 
that this heat, which escapes from the bowels of 
the earth, is in our climate at least twenty-nine 
times in 3ummer, and four hundred times in 
winter, stronger than the heat which comes to 
us from thesuq. 

This strong heat which resides in the in- 
terior part of the globe, and which, without 

voi. \, H 


50 buffon's 

ceasing to emanate externally, must, like an 
element, enter into the combination of all the 
other elements. If the sun is the parent of 
Nature, the heat of the earth must be the 
mother ; they both unite to produce, support, 
and animate organized beings, and to assimilate 
and compose inanimate substances. This in- 
ternal heat of the globe, which tends always 
from the centre to the circumference, is, in 
my opinion, a great agent in nature. We 
can scarcely doubt but it is the principal in* 
fluence on the perpendicularity of the trunks 
of trees, on the phenomena of electricity, on 
the eflfects of magnetism, &c. But as I do 
not pretend to make a physical treatise here, I 
shall confine myself to the effects of this heat 
on the other elements. It is alone sufficient 
to maintain the rarefaction of the air to the 
degree that we breathe in : it is more than 
sufficient to keep water in its state of fliiidity, 
for we have lowered the thermometers to the 
depth of 120 fathoms, and have found the 
temperature of the water was there nearly the 
same as at the like depth in the earth, 
namely, ten degrees two thirds. We must not, 
therefore, be surprized, especially as salt acts 
as a prevention, that the sea in general does 
not freeze, that fresh water freezes but to a 



certain thickness, and that the water at bottom 
always remains liquid, even in the most intense 

But of all the elements the earth is that oa 
which this internal heat must necessarily have 
produced, and still produces the greatest 
effects. This heat originally was doubtless 
much greater than it is at present ; therefore 
we must refer to it, as to the first cause, all the 
sublimations, precipitations, aggregations, and 
separations, which havebeen, and still continue 
to be made in the internal part of the globe, 
especially in the external layer which we have 
penetrated, and the matter of which has been 
removed by the convulsions of Nature, or by 
the hands of man. The whole mass of the 
globe having been melted, or liquefied, by fire, 
the internal is only a concrete or discreet glass, 
whose simple substance cannot receive any 
alteration by heat alone : there is, therefore, 
only an upper and superficial layer, which 
being exposed to the action of external causes 
united to that of the internal heat, will have 
imdergone all the modifications, differences, 
and forms, in one word, of Mineral Substances, 
which their combined actions were enabled to 

Fire, which at first sight appears to be only 
a compound of heat and light, might also be a 


5'2 fitFFON's 

modification of the matter, tlioiigh it Joes not 
essentially differ from either, and still less frora 
both (aken together. Fire never exists \yilho\it 
lieat, but it can exist without light. Ilcat 
alone, deprived of alt appcaranceof light, can 
produce the same effects as the most violent fire ; 
so can also light, when it is united. Liglit 
sterns to carry a substance in itself which has 
no need of fuel ; but fire cannot subsist without 
absorbing the air, and it becomes more violent 
in proportion to 1 lie quantity it absorbs; where- 
as light, concentrated and received into a ves- 
sel exhausted of air, acts as fire in air ; and 
heat, confined and retained in a narrow space, 
subsists and even augments with a very small 
quantity of food . Tire most general difference 
between fire, heat, and light, appears, there- 
fore, to consist in the quantity, and perliaps 
quality, of their food. 

Air is the first food of fire; combustible 
matters are oidy the second. It has been de- 
monstrated, by experiments, thata little spark 
of fire, placed in avessel well closed, in a short 
time absorbs a great quantityofair,and becomes 
e:5tinguished assoon as the quantity or quality,, 
of this food becomes deficient. By other ex- 
periments it is proved, that the most com- 
bustible ma. ters' will not consume in vessels 



well closed, although exposed to the action of 
the greatest fire. Air is, therefore, the first 
and true food of fire, and combustible matters 
would not be able to supply it withoivt tlie 
assistance and mediation of this clement. 

We have observed that heat is the cause of 
all fluidity, and we find, by comparing some 
fluids together, that more heat is requisite io 
keep iron in fusion than gold ; and more to 
keep gold than tin ; much less is necessary fo? 
wax, for Avater less than that, and still less for 
spirits of winCy and a mere trifle is sufficiejit 
for mercury, since the latter goes 187 degrees 
below what water can without losing its fluid- 
ity ; mercury^ therefore, is the most flui4 of ail 
matter, air excepted. Now this superior 
fluidity in air indicates the least degree of ad- 
herence possible between its constituting parts, 
and supposes them of such a figure as only to 
be touched at one point. It may be also ima- 
gined,, that, being endowed with so little ap- 
parent energy and mutual attraction, they are, 
for that reason, less massive, and more light, 
than those of every other body ; but that con- 
clusion appears unfounded, from the compa- 
rison of mercury, the next fluid body, but of 
which the constituting parts appear to be more 
massive and heavy than those of a!)y other 


54 buffok's 

matter, excepting gold. The greater or lesser 
fluidity, does not, therefore, indicate that the 
parts of the fluid are raore or less weighty, but 
only that their adherence is so much the less, 
and their separation so much the easier. 

Air, therefore, of all known matter, is that 
which heat divides the easiest, and is very 
near the nature of fire, whose property consists 
in the expansive motions of its parts ; and it 
is from this similarity that air so strongly 
augments the activity of fire, to which it is 
the most powerful assistant, and the most in- 
timate and necessary food. Even combustible 
matters will not keep it alive if deprived of 
air, for under this privation the most intense 
fire will not burn ; but a single spark of air is 
sufficient to kindle them, and in proportion as 
it is supplied with that clement the fire be- 
comes strong, extended, and devouring. 

Artificial phosphorus, and gunpowder, seem, 
at first, to be an exception, for they have no 
need of the assistance of renewed air to inflame 
and wholly consume them: their combustion 
may be performed in the closest vessels, but 
that is because those matters, which are also 
the most combustible, contain the necessary 
quantity of air in their substance, therefore they 
have no need of tl:e assistance of foreign air. 



This seems to indicate that the most essential 
difference between combustible matters and 
those which are not so, consists in the latter 
containing only a few or none of the light, 
ethereal, and oily matters susceptible of an ex- 
pansive motion, or, at least, if they contain 
them, that they are fixed, so that they cannot 
exercise their volatility whenever the force of the 
fire is not strong enough to surmount the force 
of adhesion which retains them united to the 
fixed parts of matter. It mjiy be said that this 
induction is confirmed by a number of observa- 
tions well known to chemists ; but what ap- 
pears to be less so, and which, never(heless, is 
a necessary consequence of it, is, that all matter 
may become volatile when the expansive force 
of the fire can be rendered superior to the at- 
Iraclive force which holds the parts of matter 
united; for though to produce afire suffi- 
ciently strong it may require better constructed 
mirrors than any at present known, yet we 
are certain that fixity is only a relative qua- 
lity, and that there is no matter absolutely so, 
since heat dilates the most fixed bodies. Now 
is not this dilation the index of a beginning 
separation, that may be augmented with a de- 
gree of heat to fusion, and with a still greater 
heat to volatilisation ? 



Combttstioii supposes somediing more than 
volattlisationi; it is not sufficient that the parts 
of matter be sufficiently separated to be car- 
jied off by those of heat ; they must also be of 
an analogous nature to tire ; without that, 
m<?rcury, being the most fluid next to air, 
:\youUi also be the most combustible^ >\hereas 
experience demonstrates, that though very 
volatile it is not combustible. Matter is, in 
general, composed of four principal subr 
stances, called ekmenfSy that is , earth, water, 
air, and fire. Those in which earth and water 
predominate will be fixed, and will only be- 
come volatile by the action of heat ; and those 
which contain most air and fire will be the 
only real combustibles. The great difficulty 
Jhere is. clearly to conceive how air and fire, 
both so volatile, can fix and become consti- 
tuent parts of all bodies. 

Fire, by absorbing air, destroys the spring. 
Now there are but two methods of destroying 
a spring, either by compressing it till it break?, 
or extending it till it loses its effect. It is 
l^lain tliat fire cannot destroy air by compres- 
sion, &ince the least degree of heat rarefies it; 
on tlie contrary, by a very strong heat the 
rarefaction of llie air will be so great that it 
will occupy a space thirteen times more ex- 
tended than that of its general volume; and 



by this means the spring becomes Weakened, 
and it is in this state that it can become fixedj 
and unite with oth«r bodies. 

Light, wliich falls on bodies, is not merely 
reflected, but remains in quantities oh th# 
small thickness of the stirface which it strikes j 
consequently it loses its mot ion, extends, is fix* 
ed, and becomes a constHuent part of all t4ial 
it penetrates. Let us add this light, trftfts- 
formed and fixed in bodies, to the Above air5 
and to both, the constant and actual heat of th* 
terrestrial globe, -whose sum is much greater 
than that which comes from the stin, and thdft 
It will appear to be not only one of the greatesl 
springs of the mechanism of Nature, but a« 
element with which the whole raatteft of the 
globe is penetrated. 

If we consider more particularly the nature 
of combustible matters, ^g shall fhid, that th^y 
all proceed originally from vegetables -^^^ ani- 
mals ; in a woTd, from bodies placed oti tht 
surface of the globe, which the Son enlighten^, 
Leats, and vivifies. Wood, bitumen, rmn^ 
coals, fat and oil, by espTessiOfi, 'vrax, and ^«^j 
are substances ptocecding immrdiatety from 
animals and Vegetables. Turf, fcfesrl. Coal, 
amber, liquid, or concrete biturrreTTs, afe the 
productions of their mixture, and their ^Vcem* 
VOL. x\ I position. 

58 buffon's 

position, wbose ulterior waste forms sulphurs^ 
and the combustible parts of iron, tin, pyrites^ 
and every inflammable mineral. I know, 
that this last assertion will be rejected by those 
who have studied nature only by the mode of 
chemistry ; but I must request Ihem to con- 
sider, that their method is not that of nature, 
and that it cannot even approach it without 
banishing all those precarious principles, 
those fictitious beings which they play upon, 
without being acquainted with (hem. 

But, without pressing longer on those general 
considerations, let us pursue in a more direct 
and particular manner the examination of fire 
and its effects. The action of fire depends 
much on the manner in which it is applied ; 
and the effects of its motion, on similar sub- 
tances, will appear different according to the 
mode in which it is administered. I conceive 
that fire should be considered in three different 
states, first relative to its velocity ; secondly, 
as to its volume ; and thirdly, as to its mass. 
Under each of these points of view, this ele- 
ment, so simple, and so uniform to all appear- 
ance, will appear extremely different. The 
velocity of fire is augmented without the ap- 
parent volume being increased, every time 
that in a given space and filled with com- 


biibtible matters, its action and expansion is 
pressed by augmenting the velocity of the air 
by bellows, caverns, ventilators, aspirative 
tubes, &c. all of which accelerate more or less 
the rapidity of the air directed on the fire. 
The action of fire is augmented by its volume, 
when a great quantity of combustible matters 
is accumulated, and the heat and fire are 
driven into the reverberatory furnaces, which 
comprehend those of our glass, porcelain, and 
pottery manufactories, and all those wherein 
metals and minerals are melted, iron excepted. 
Fire acts here by its volume, and has only its 
own velocity, since the rapidity is not aug- 
mented by the bellows, or other instruments 
which carry air to the fire. 

There are many modes of augmenting the 
action of fire by its velocity or volume ; but 
there is only one way of augmenting its mass ; 
namely, by uniting it in the focus of a burning 
glass. When we receive on the refracting, 
or reflecting mirror, the rays of the sun, or 
even those of a well-kindled fire, we unite 
them in so much the less space, as the mirror 
is longer, and the focus shorter ; for example, 
by a mirror of four feet diameter, and one 
inch focus, it is clear, that the quantity of 
light, or fire, which falls on the four- feet mirror, 


&f buffon's 

will be united in the space ofoueincli, that is, 
it will be 2SU4 times denser than it was, if all 
the incident matter arrived to tliis focus with- 
out any loss, and when eyen the loss is two 
thirds or three fourths, the mass of fire concen- 
trated in the focus of this mirror, will alwajs 
besije or seven hundred times denser than on 
the surface. In this, as in all other cases, 
tibe mass goes by the contraction of the vo- 
lume; and the fire which we thus augment 
the density of, has all the properties of a mass 
of matter; for, independently of the action of 
heatj by which it penetiates bodies, it impels 
and displaces them qs a solid moving body 
which strikes another would do. 

Each of these modes of administering fire, 
and increasing either the velocity, volume, or 
mass, often produce very different effects on 
the same sHibstances ; insomuch, that no reli» 
ance is to be placed on any thing that cannot 
be woirked at the same time, or successively, 
b^r all three. In the like manner, as I divide 
in^thrcc general proceedings the administra- 
Honxti this element, I divide every matter that 
can be submitted toits action iato three classes. 
JPassing over for the present those which are 
purely combustible, and which immediately 
proceed £rom aftimals and vegetables ; we 



proceed to minerals, in the first class of which 
we reckon those mineral matters, which this 
action, continued for a long time, renders 
lighter, as iron ; in the second, such as it ren- 
ders heavier, as lead ; and in the third class, 
are those matters on which, as gold, this action 
of fire does not appear to produce any sen- 
sible effect, since it does not at all alter their 
weight. All existing matters, that is, all sub- 
stances simple and compounded, will necessa- 
rily be comprized under one of these three 
classes ; and experiments on them by the three 
proceedings, which are not difficult to be made, 
and only require exactness and time, might 
develope many useful discoveries, and prove 
very necessary to build on real principles the 
theory of chemistry, which has hitherto been 
carried on by a precarious noraenclatura, and 
on words the more vague as they are the more 

Fire is the lightest of all bodies, notwith- 
standing which it has weight, and it may be 
demonstrated, that even in a small volume ittS 
jcally heavy, as it obeys, like all other raatters, 
the general law of gravity, and consequently 
must have connections or affinities with other 
bodies. All matters it renders more weighty 
will be those with which it has the greatest 
aflittiiy. On€ €vf the effects of this affinity in 


62 hufton's 

the matters is io relaiii the sui)S)tance even of 
fire, with which it is incorporated, and tli is in- 
corporation supposes that lire not only its 
licat and elasticity, but even all its motion, 
since it fixes itselt in these bodies, and becomes 
a constituent part. From wliich it may be 
irnai^ined lljat there is fire under a fixed and 
concrete form in almost every body. 

It is evident, that all matters, whose weight 
increases by the action of fire, are endowed 
with an attractive force superior to the ex* 
pansive, the fiery particles of which are ani- 
mated ; this bein£ij extinguished the motion 
ceases, and the clastic and fugitive particles 
become fixed, and take a concrete form. Thus 
matters, whose weight is increased by fire, as 
tin, lead, &c. are substances which, by their 
affinity with fire, attract and incorporate. All 
matters, on the contrary, which, like iron, 
copper, &c. become lighter in proportion as 
they are calcined, are substances whose at- 
tractive forces, relative to the igneous parti- 
cles, is less than the expansive force of fire ; 
and hence tlie fire, instead of fixing in these 
matters, carries ofl:' and drives away the least 
adherent parts which cannot resist its impul- 
sion. Those which, like gold, platina, silver, 
&c. neither lose nor acquire by the application 
of fire, aresubstanccswhich, having no affinity 



with firCy and not being able to iini(c, 
consequently, either re ain or accompany it 
when it is carried off. It is evident that the 
matters of \-\e two first classes Iiave a certain 
degree of affinity with fire, since those of the 
second class are loaded with fire, which ihey 
retain ; and the fire loads itself with (hose of 
the first class, which it carries off; whereas 
the matters of ;he third class, to which it 
neither lends nor borrows, have not any affinity 
or attraction witli it, but are indifierent to its 
action, which can neither uniiatuializc nor 
even change them. 

This division of every matter into three 
classes, relative to the action of fire, docs not 
exclude the more particular and less absolute 
division of all matters into two other classes, 
hitherto regarded as relative to tlieir own na- 
ture, which is said to be always vitrifiable, or 
calcareous. Our new division is only a more 
elevated point of view, under which we must 
consider them, to endeavour to deduce there- 
from even the agent that is used by the rela- 
tions fire can have with every substance to 
which it is applied. 

We might say, with naturalists, that all is 
vitrifiable in Nature, excepting that which is 
calcareous : that quartz, chrystals, precious 


64 buffon's 

stones, flints, granites, porphyries, agates, 
gypsums, clays, lava, pumice stone, with all 
metals and other minerals, are vitrifiable 
either by the fire of our furnaces, or that of 
mirrors; whereas marble, alabaster, stones, 
chalk, marl, and other substances which pro- 
ceed from the residue of shells and madrepores, 
cannot be reduced into fusion by these means. 
Nevertheless I am persuaded, that if the power 
of our furnaces and mirrors were further in- 
creased, we should be enabled to put these cal- 
careous matters in fusion ; since there are a 
multiplicity of reasons to conclude, that at the 
bottom their substance is the same, and that 
glass is the common basis of all terrestrial matter. 
By my own experiments I have found, that 
the most powerful glass furnaces is only a weak 
fire, compared with that of bellows furnaces ; 
and that fire produced in the focus of a good 
mirror, is stronger than that of the most glow- 
ing fire of a furnace. I have kept iron ore 
for thirty -six hours in the hottest part of the 
glass furnace of Rouclle, in Burgundy, without 
its being melted, agglutinated, or even in any 
manner changed ; whereas, in less than twelve 
hours this ore runs in a forge furnace. I have 
also melted, or volatilized, by a mirror many 
matters which neither the fire, nor reverbera- 

NATURAL niSTonir* 60 

tory furnace, nor the most powerful bellows 
furnace could cause to run. 

It is commonly supposed, that flame is the 
hottes* part of fire, yet nothing is more errone- 
ous than this opinion; the contrary maybe 
demonstrated by the most simple and familiar 
experiments. Offer to a straw fire, or even 
to the flame of alighted faggot, a cloth to dry 
or heat, and treble the time will be required to 
what would be necessary if presented to a bra- 
sier without flame. Newton very accurately 
defines flame to be a burning smoke, and this 
smoke, or vapour, has never the same quanti* 
iy or intensity of heat as the combustible body 
from which it escapes. By being carried up- 
wards a,nd extending, it lias the property of 
communicating fire, and carrying it further 
than the heat of the brasier, which alone might 
not be, sufficient to communicate it when even 
very near. 

The communication of fire merits a particu- 
lar attention. I found, after repeated reflec- 
tions that besides the assistance of facts which 
appear to have a relation to it, that experi- 
ments were necessary to understand the man^ 
ner in which thisoperation of Nature is made. 
Let us recieve two or three thousand weight of 
irpn in a mould at its issuing from the furnace ; 
tliismetal in ashorttimeloses its incandescence, 
Vol. X, K and 

66 buffon's 

and ceases from its redness, according to the 
thickness of the ingot. If at the moment its 
redness leaves i(, it is drawn from the mold, 
the under parts will be still red, but this colour 
will fly off. Now so long as the redness sub- 
sists, we can light combustible matters by ap- 
plying tliem to the ingot ; but as soon as it has 
lost its incandescent state, lliere are numbers of 
matters which it will not get fire to, although 
the heat which it diffuses is, perha[3S a hun- 
dred times stronger than that of a straw fire, 
which would inflame them.. This made me 
think that fla-ne being necessary to the com- 
munication of fire, there is therefore a flame in 
all incandescence. The red colour seems, in 
fact, to indicate it ; and indeed I am convinced, 
that combustible, and even the most fixed mat- 
ters, such as gold and silver, when in an in- 
candescent stale, are surrounded with a dense 
flame which extends only to a very short dis- 
tance, and which is attached to their surface ; 
and I can easily conceive, that when flame be- 
comes dense to a certain degree, it ceases from 
obeyifig the fluctuation of the air. This white 
or red body, which issues from all bodies in 
incandescence, and which strikes our eyes, is 
the evaporation of tliis dense flame which sur- 
rounds the body by renewisjg itself incessantly 
on its surface ; aiiid even the light of the sun, 



which emits such an amazino' brii>'htaess, I 
presume to be only an evaporation of the dense 
state that con^tantly plays on its surface ; anc| 
TV'hich we must regard as a true flame, more 
pure and dense than any proceeding from our 
combustible matters. 

It is, theref )re, by light that fire communi- 
cates, and heat alone cannot produce the same 
ofFect as when it becomes very strong to be iii- 
jninous. Even water, that dchtruclive clement 
to fire, by which aloiie we can prevent its pro- 
gress, nevertheless communicates when in a 
well-closed vessel, such as Papi.i's digester, 
where it is penetrated with a sufficient quantity 
of fire to render it luminous, and capable of 
melting lead and tin, wiiereas when it is oidy 
boiling, far from communicating fire, it extin- 
guishes it immediately. Jt is true, that heat 
alone is sufficient to prepare and dispose com- 
bustible bodies for inflammation, by driving 
off the humid parts from bodies ; and what is 
very remarkable, this heat, which dilates all 
bodies, does notdesistfVom hardening them by 
drying. I have an hundred times discovered, 
by examining the stones of my great furnaces, 
especially the calcareous, they increased in 
hardness in proportion to the time tliey had 
undergone the heat, and ihcy also at the same 
time became specifically heavier. From this 


CS buffon's 

circumstance, I think an induction may bo 
drawn, which would prove, and fully confirm, 
that heat, although in appearance always fu- 
gitive and never stable in the bodies which it 
penetrates, neverthelsss deposits in a positive 
manner many parts which fixes there even in 
greater quantities than the aqueous and other 
parts which it has driven off. But what ap- 
pears very difficult to be reconciled, this same 
calcareous stone, which becomes specifically 
heavier by the action of a moderate heat a 
long time continued, becomes near a half 
lighter, when submitted to a fire sufficient for 
its calcination, and, at the same time, not only 
loses all the hardness it had acquired by the 
action of heat, but even the natural adherence 
of its constituting parts. 

Calcination generally received, is, with re- 
spect to fixed and incombustible bodies, what 
combustion is to volatile and inflammable. 
Calcination, like combustion, needs the assist- 
ance of air ; it operates so much the quicker, 
as it is furnished with a greater quantity of 
that element, without which the fiercest fire 
cannot calcine nor inflame any thing, except 
such matters as contain in themselves all the 
air necessary for those purposes. This neces- 
sity for the concurrence of air in calcination, 
as in combustion, indicates, that there are more 



tbings common between them than has been 
suspected. The application of fire is the prin- 
ciple of both ; that of air is the second cause, 
and abiiost as necessary as the first ; but these 
two causes are equally combined, according 
as they act in more or less time, and with 
more or less power on different substances. 

Combustion operates almost instantaneously ; 
calcination is sometimes so lon^:, as to be 
tliought impossible ; for in proportion as mat- 
ters are more incombustible, the calcinafion 
is there more slowly made ; and wlien the con- 
stituent parts of a substance, such as gold, are 
not only incombustible, but appear so fixed as 
not to be volatilized, calcination produces no 
effect. They must both, therefore, be con- 
sidered as effects of the same cause, whose 
two extremes are delineated to us by phos- 
phorus, which is the most inflammable of 
all bodies, and by gold, which is the most 
fixed and least combustible. All substances 
comprized between these two extremes, will 
be more or less subjected to tlie efiects of 
combustion and calcination, according as they 
approach either of tliem ; insomuch, that 
in the middle points there will be found 
substances that endure an almost equal degree 
of both ; from which we may conclude, that 
all calcination is always accopmanicd with a 


70 buffon's 

little combustion, and all combustion uiili a 
little calcination. Cinders and other residue 
of the most combustible matters, demonstrate 
that fire has calcined all the parts it lias not 
burned, and consequently, a little calcination 
is found here with combustion. The small 
flame which rises from most matters, tiiat are 
calcined, demonstrates also that a slight 
combustion is made Tlius, we must not se- 
perate these two effects, if w'e would find out 
the results of the action of fire on the differ- 
ent sub>tances to which it is rspplied. 

But it may be said, that comb u'-tion always 
diminishes the volume or mass, on account of 
the quantity of matter it consumes ; and that, 
on the contrary, calcination increases the 
•weight of many substances. Ought we then 
to consider these two effects whose results are 
so contrary, as effects of the same nature ? 
Such an objection appears well-founded, 
and deserves an answer, especially as this 
is the most difficult point of the question. 
For that purpose let us consider a matter in 
"which we shall suppose one half to be fixed 
parts, and the other volatile or combustible. 
By the application of fire to this, all the vola- 
tile or combustible parts will be raised up or 
burnt, and consequently separated from the 
whole mass ; from hence this mass or quantity 



of matter ^vill be found diminished one half, 
as Ave see it in calcareous stones, which lose near 
half their weight in the fire. But if we con- 
tinue to apply the iire for a very longtime to 
the other half, composed of fixed parts, all 
combustion and volatilization being ceased, 
that matter, instead of continuing to lose its 
mass, must increase at the expense of the air 
and fire with which it is penetrated ; and (hose 
are matters already calcined, and prepared by 
Nature to the degree where combustion 
ceases, and consequently susceptible of in- 
creasing: the weisrht from the first moment of 
the application. We have seen, that light 
extinguishes on the surface of all bodies 
which do not reflect ; and that heat, by long 
residence, fixes partly in the matters which it 
penetrates ; we know also that air is neces- 
sary for calcination, or combustion, and the 
more so for calcination as having more fixity in 
the external parts of bodies, and becomes a 
constituent part : hence, it is natural to ima- 
gine, that this augmentation of weight pro- 
ceeds only from the addition of the particles 
of ligh(, heat, and air, which are a length 
fixed and united to one matter, against which 
they have made so many efforts, witliout being 
able either to raise or burn them. This appears 



clearly to be the fact, for if wo afterwards pre- 
sent a combustible substance to them thej ^vill 
quit the fixed matter, to xvhich they were only 
attached through force, retake their natural 
motion, elasticity, and volatility, and all de- 
part with it ; frcra hence, metal, orcalcinized 
matter, to which these volatile parts has been 
rendered, retakes its pristine form, and its 
weightis found diminished by the whole quan- 
tity of fiery and airy particles which were fixed 
in it, and whicli had been ju!>t raised by this 
new combustion. All this is performed by the 
sole law of affinities ; and their seems to be no 
more difficulty to conceive how the lime of a 
metal is reduced, than to understand how it is 
precipitated in dissolution ; the cause is the 
same, and the effects are similar. A metal dis-. 
solved by an acid, will precipitate when to this 
acid another substance is offered with which 
it has more affinity than metal, the acid (hen 
quits it and falls to the bottom. So,likewcse, 
this metal calcines, tliat is, loaded with parts 
of air, heat, and fire, which being fixed, keeps 
it under the form of a lime, and will precipi- 
tate, or be reduced, when presented to this fire 
and fixed air, from the combustible matters 
with which they have more affinity than with 
the metal ; the latter will retake its first form 



as soon as U is disembarrassed from tliis su^jcr- 
fluous air and fire, at the ex pence of the com- 
bustible matters oii'ered to it, and tlie volatile 
parts it had lost. 

IthinkI have nowdemonstratcdjthsit all the 
litile laws of chemical afHiitlles, Vrliich ap-^ 
j)earcd so variable and different, are no other 
llian the general laws of attraction, common 
to all matter ; that this ^reat law, always 
constant and the samcj appeared oidy to vary 
in its expression, ^vliich cannot be the same 
^vllen the figure of bodies enters, like an ele^ 
inent, into their distance. With this new key 
we can unlock the mobt profound secrets of 
Nature; we can attain the knowledge of 
the figufe of the primitive parts of difil^rent 
substances • assign the laws and degrees of 
their affinities; determine the forms which 
they take by re-uniting, &c. I think also I 
have made it appear that impulsion depends 
on attraction ; and thatj although it may be 
considered as a different forcCj it is, notwith- 
standing, a particular effect of i!ils sole and 
general one. I have shewn the conmiuni- 
cation of rriotion to be impossible without 
a springy whence I have concluded, that 
all bodies in Nature are more or less elas- 
tic, and that there is not one perfectly 
Vol, X. L hard 5 

74 ijuffon's 

hard ; that is, entirely deprived of a spring, 
since all are susceptible of receiving motion. 
I liave endeavoured to shew how this sole 
force may change direction, and attraction 
become repulsion ; and from these grand 
principles, which are all founded on rational 
mechanics, I have sought to deduce the prin- 
cipal operations of Nature, such as the pro- 
duction of light, heat, and fire, and . their 
action on different substances ; this last object 
%vhich interests us the most is a vast field, 
but of which I can only cultivate a little spot, 
yet I presume I may render some assistance, 
by putting into more capable and laborious 
hands the instruments I made use of. These 
instruments were the three modes of making 
use of fire, that is, by its velocity, volume, 
and mass ; by applying it* concurrently to the 
three classes of substances, which either lose, 
gain, or are not affected by the application of 
fire. The experiments which I had made on 
the refrigeration of bodiesjon the real weight of 
fire, on the nature of flame, on tlie progress of 
heat, or its communication, its diperdition,i(s 
conc(*nt ration, or its violent action without 
flame, &c. are also so many instruments which 
will spare much labour to those who choose to 
avail themselves of them, and will produce an 
ample harvest of knowledge . 




BY our former observations it appears that 
air is the necessary and first food of fire, which 
can neither subsist nor propagatebut by what 
it assimilates, consumes, or carries off, of tliat 
element, whereas of all material substances, 
air is that which seems to exist the most in- 
dependently of the aid or presence of fire; for 
although it habitually has nearly the same heat 
as other matters on the surface of the earth, 
it can do without it and requires infinitely less 
than any of the rest to support its fluidity, 
since the most excessive cold cannot deprive 
it of that. The strongest condensations are 
not capable of breaking its spring ; the 
active fire, in combustible matters, is the. 
only agent which can alter its nature by rare- 
fying and extending its spring to the point of 
rendering it ineff^^ctual, and thus destroying its 
elasticity. In this state, and in all the links 
which precede, the air is capable of re-assuming 
its elasticity, in proportion as the vapours of 
combustible matters evaporate and separate 
from it. But if the spring have been totally 


/^^^ BUFFON'S 

Avcakcned and extended that it cannot re-instate 
itself, from having lost all its elastic power, the 
air, volatile as it might before have been, be- 
comes a fixed substance Avhich incorporates 
■with the other substances, and forms a consti- 
tuent part of all those to which it unites by con- 
tact. Under this new form it can no longer 
forsake the fire, except to unite, like fixed 
matter, to other fixed matters; and if there 
remain some parts insCj a able from fire, they 
tlien make a portion of that element serve 
it for a base, and are deposited with it in the 
subetance tliey heat and penetrate together. 
This efi'ect is manifested in all calcinations, 
and is the more sensible as the heat is longer ; 
but combustion demands only a small time 
to completely effectuate the same. If we 
wish to hasten calcination the use of bellows 
may be necessary, not so much to augment 
the heat of the fire as to establish a current 
of air on the surface of the matters ; yet it is 
not requisite for the fire to be very fierce to 
deprive air of its elaslicity, for a very mode^ 
rate heat, when constantly applied on a small 
quantity, is sufficient to destroy the spring ; 
and for this air, without spring, to fix it- 
self afterwards in bodies, there is oidy a little 
more or less time required, according to the 
afl&nity it may have under tliis new form, with 



the matters to Tvhich it unites. The heat of 
the body of animals, and even vegetables, is 
sufficiently powerful to produce this effect. 
The degrees of heat are different in different 
lands of animals : birds are the hottest, from 
M'hicli we pass successively to quadrupeds, 
man, cetaceous animals, reptiles, fish, insects, 
and, lastlj>,to vegetables, whose heat is so tri- 
fling as to have made some naturalists declare 
they had not any, although it is very apparent, 
and in wijiter surpasses that of the atmosphere. 
I have frequently observed in trees that were 
cut in cold weather, that their internal part 
was sensibly warm, and that this heat remained 
for many minutes. This heat is only moderate 
while the tree is young and sound, but as soon 
as it grows old the heart heats by the fermen- 
tation of the pith, which no longer circulates 
there with the same freedom ; and as soon as 
this heat begins the centre receives a red tint, 
which is the first index of the perishing state 
of the tree, and the disorganization of the 
wood. The reason naturalists have not found 
there was a difference between the temperature 
of the air, and the heat of vegetables is, be- 
cause they have made their obseryations at a 
bad time of the year, and not paid attention, 
that in the summer the heat of the air exceeds 


"78 buffoxn's 

that of the internal part of a tree; whereas in 
winter it is quite the contrary. They have not 
. remembered that the roots have constantly the 
deicree of heat which surrounds them, and 
that this heat of the internal part of the earth 
is, daring all winter, considerably greater than 
that of the air, and the surface of the earth. 
.They did not consider that the motion alone of 
the pith, already warm, is a necessary cause of 
heat, and that this motion, increasing by the 
action of the sun, or by an external heat, that 
of vegetables must be so much the greater as 
the motion of their pith is more accelerated, 

Here the air contributes to the animal and 
vital heat, as we have seen that it does to the 
action of fire in combustible and calcinable 
matters. Animals, which have lungs, and 
which consequently respire the air, have 
more heat than those deprived of them ; and 
the more the internal surface of the lungs 
is extended, and ramified in a greater num- 
ber of cells, the more it presents greater su- 
perficies to the air which the animal draws by- 
inspiration; the more also its blood becomes 
hotter, the more it communicates heat to 
all parts of the body it nourishes, and this 
proportion takes place in all known animals. 



Birds, relatively to the volume of their body, 
have lungs considerably more extended than 
man or quadrupeds. Reptiles, even those with 
a voice, as frogs, instead of lungs have a 
simple bladder. Insects which have little or 
no blood breathe the air only by some pipes, 
&c. Thus taking the degree of the temperature 
of the earth for the term of comparison, I have 
observed that this heat being supposed ten de- 
grees, that of birds was nearly thirty-lhree, 
that of some quadrupeds more than thirty-one 
and a half, that of man thirty and a half, or 
thirty-one, whereas that of frogs is only fifteen 
or sixteen, and that of fishes and insects only 
eleven or twelve, which is nearly the same as 
that of vegetables. Thus the degree of heat 
in man and animals depends on the force and 
extent of the lungs; these are the bellows of 
the animal machine : the only difficulty is to 
conceive ho.v they carry the air on (he fire 
"which animates us, a fire whose focus seems 
to be indeterminate ; a fire that has not even 
been qualified with this name, because it is 
without flame or any apparent smoke, and its 
heat is only moderate and uniform. How- 
ever, if we consider that heat and fire are ef- 
fects, and even elements of the same class ; 
that heat rarefies air, and, by extending its 


so BUFFOS ^$ 

spring, it may render it without effect ; wd 
may imagine, tbat I be air drawn by our lungs 
being greatly rarefied, loses its spring in 
the bronchiae and little vesicles, where it is 
soon destroyed by the arterial and venous 
blood, for these blood-vessels are separated 
from the pulmonary vesicles by such thin di* 
visions that the air easily parses into the 
blood, where it produces the same effect as 
upon common fire, because the heat of this 
blood is more than sufficient to destroy the 
elasticity of the particles of air, and to drag 
them under this new form into all the roa^s 
of circulation. The fire of the animal bbay 
differs from common fire only in more or 
less ; the degree pf heat is less, hence there is 
no flame, because the vapours, which represent 
the smoke, have not heat enough to inflame ; 
every other effect is the same : the respiration 
of a young animalabsorbs as much air as the 
light of a candle, for if inclosed in vessels of 
equal capacities, the animal dies in the same 
time as the candle extinaruishes : nothini^ can 
more evidently demonstrate that the fire of 
the animal a|id that of the candle are not of 
the same class but of the same nature, and to 
which the assistance of the air is equally ne- 



Vegetables, and most insects, instead of 
lungs, have only aspiratory tubes, by which 
they pump up the air that is necessary for 
them ; it passes in very sensible balls into the 
pith of the vine. This air is not only pumped 
up by the roots but often even by the leaves, 
and forms a very essential part of the food of 
the vegetable which assimilates, fixes, and 
preserves it. Experience fully confirms all 
we have advanced on this subject, a.nd that all 
combustible matters contain a considerable 
quantity of fixed air, as do also all animals 
and vegetables, and all their parts, and the 
waste which proceeds therefrom ; and that the 
greatest number likewise include a certain 
quantity of elastic air. And, notwithstanding 
the chimerical ideas of so me chem ists, respecting 
phlogiston, tliere does not remain the smallest 
doubt but that fire or light produces, with the 
assistance of air, all tiie efiects thereof. 

Minerals, which like sulphur and pyrites, 
contain in their substance a quantity of the ul- 
terior waste of animals and vegc(ables, con- 
tain thence combustible matters, which, like 
all other, contain more or less fixed air, but 
always much less than the purely animal or 
vegetable substances. Tliis fixed air can be 
equally removed by combustion. In animal 
and vegetable matters it is disengaged by 
VOL. X. M simpk- 

S^ buffon's 

simple fermentation, wliicli, like conibuhtion, 
has always need of air for its operation. Sul- 
phurs and pyrites are not the only minerals 
which must be looked upon as combustible, 
there are many others which I shall not here 
enumerate, because it is sufficient to remark, 
^heir degree of combustion depends commonly 
on the quantity of sulphur which they contain. 
AH coml)Ustible minerals originally derive this 
property either from the mixture of animal or 
vegetable parts which are incorporated with 
them, or from the particles of light, heat, and 
air, which, by the lapse of time, are fixed in 
their internal part. Nothing, according to 
my opinion, is combustible but that which has 
been formed by a gentle heat, that is, by these 
same elements combined in all the substances 
which the sun brightens and vivifies, or in 
that which the internal heat of the earth fo- 
ments and unites. « 

The internal heat of the globe of the earth 
must be regarded as the true elementary fire ; 
it is always subsisting and constant ; it enters, 
like an clement, inio all the combinations of 
the other elements, and is more than sufficient 
to produce the same effi^cts on air as actual 
fire on animal heat; consequently this internal 
heat of the earth will destroy the elasticity of the 
air, and render it fixed, which being divided 



into minute parts \vill enter into a great num* 
ber of substances, from hence they will contain 
articles of fixed air and fire, which are the first 
principles of combustibility ; but they will be 
found in difierent quantities, according to their 
degree of affinity witli the substance, and this 
degree will greatly depcnil on the quantity 
these substances contain of animal and vege- 
table parts, which appear to be the base of ail 
combustible matter. Most metallic mineral, 
and even metals, contain great quantities of 
combustible parts; zinc, antimony, iron, cop- 
per, &c. burn and produce a very brisk flame, 
as long as the combustion of these inflammable 
parts remains, after which, if the fire be con-!- 
tinued, the calcination begins, during whicli 
there enters into them new parts of air and 
heat, which fixes, and cannot be disengaged 
but by presenting to them combustible matters, 
with which they have a greater affinity than 
with those of the mineral, witli which they 
are only united by the effort of calcination. 
It appears to me, that the conversion of me- 
tallic substances into dross, and their repro- 
duction, might be very clearly understood 
Avithout applying to secondary principles, or 
arbitrary hypotheses, for their explanation. 

Having considered tlje action of fixed air in 
,lhe most secret operations of nature, let us take 

a yipw 

a view of it when it resides in bodies under an 
elastic form ; its effects are then as variable as 
the degrees of its elasticity, and its action, 
though always the same, seems to give different 
products in different substances. To bring this 
consideration back to a general point of view, 
we "will compare it with water and earth, as 
"we have already compared it with fire ; the 
results of this comparison between the four 
elements will afterwards be easily applied to 
every substance, since they are all composed 
merely of these four real principles. 

The greatest cold that is known, cannot de- 
stroy the spring of the air, and the least heat is 
sufficient for that purpose, especially when this 
fluid is divided into very small particles. 
But it must be observed, that between its state 
of fixity, and tliat of perfect elasticity, there are 
all the links of the intermediate states, in 
one of which it always resides in earth and 
water, and all the substances which are com- 
posed of them ; for example, water, which ap- 
pears so simple a substance, contains a certain 
quantity of air, which is neitlier fixed nor 
elastic, as is plain from its congulation, ebul- 
lition, and rcsistence to all compression, &c. 
Experimental philosophy demonstrates, that 
water is incompressible, for instead of shrink- 
ing and entering into itself when pressed, it 



passes tlirou<?li the most solid and tliickest 
vessels^; which could not be the case if the 
air it contained were in a state of full elasti- 
city. The air contained therefore in Avater, 
is not simply mixed therewith, but is united 
in a state where its spring is not sensibly ex- 
ercised ; yet the spring is not entirely de- 
stroyed, for if we expose water to congelation, 
the air issues from its internal part, and unites 
on its surface in elastic bubbles. This alone 
suffices to prove, that air is not contained in 
water under its common form, since being spe- 
cifically 850 times lighter, it would be forced 
to issue out by the sole necessity of the prepon- 
derance of water; neither under an affixed 
form, but only in a medium state, from whence 
it can easily retake its spring, and separate 
more easily than from every other matter. 

It may, with some justice, be objected that 
cold and heat never operate in the same 
m6de, and that if one of these causes gives to 
air its elasticity, the otlier must destroy it, 
and I own that in general it is so, but in this 
particular they produce the same effect. It 
is well known that water, frozen or boiled, 
reabsorbs the air it had lost as soon as it is 
liquefied or cooled . The degree of affinity of 
air with water, depends, therefore, in a great 
measure, on its temperature, Mhich in its li- 

B6 buffon's 

^quid state; is nearly the same as that of the 
general heat, to the surface of the earth : the 
air with which it has much affinity penetrates 
it as soon as it is divided into small parts, yet 
the degree of elementary and general heat, 
"weakens their spring so as to render them in- 
effectual as long as the water preserves this 
temperature ; but if the cold penetrate, or this 
degree of heat diminish, then its spring will 
be re-established by the cold, and the elastic 
bubbles will rise jto the surface of the water 
ready to freeze; if, on the contrary, the tem- 
perature of the water is increased by an exr 
ternal heat, the integrant parts become too 
much divided, they are rendered volatile, and. 
the air with which they are united, rises an4 
escapes with them. Water and air have much 
greater connections between them than oppor 
site properties, and as I am well persuaded, 
tliat all matter is convertible, and that the ele- 
ments may be transformed, I am inclined to 
believe, that water can change into air when 
sufficiently rarefied to raise up in vapours, for 
the spring of the vapour of the water is evei^ 
more pow erful than the spring of the air. 

Experience has taught me that the vapours 
of water can increase the fire in the same 
manner as- common air ; and this air, which 
we may regard as pure, is always mixed with 

a very 


a very great quantity of water ; but it must 
be remarked, as an observation of much im- 
portance, thiit the proportions of the mixtures 
are not nearly the same in these two elements. 
It may be said in general that there is much 
less air in water than water in air. In consi- 
dering this proportion we must refer to the 
volume and mass. If we estimate the quantity 
of air contarinedin water by the volume it will 
appear nil, since the volume is not in the least 
increased. Thus it is not to the volume that 
"we must relate this proportion, it is alone to 
the mass, that is, to the real quantity of mat- 
ter in one and the other of these two elements 
that we mubt compare that of their mixture, 
by which we shall percelre that the air is much 
more aqueous than the water is aerial^ perhaps 
in proportion of the mass, that is, eight hun- 
dred and fifty times. Be this estimation eit^ier 
too strong or too weak we can derive this in- 
duction from it, that water must change more 
easily into air than air can transform into 
water. The parts of air, although susceptible 
of being extremely 'divided, appear to be 
more gross than those of water, since the 
latter passes through many filtres which air 
cannot penetrate ; since the vapours of water 
are only raised to a certain height in the air ; 
and, in short, since air seems to imbibe water 


83 buffon's 

like a sponge, to contaia it in a large quantij, 
and that the container is certainly greater than 
the contained. 

In the order of the conversion of the ele- 
ments it appears to me, that water is to air 
what air is to fire, and that all the transforma- 
tions of nature depend on them. Air, like 
the food of fire, assimilates with it, and is 
transformed into this first element. Water, 
rarefied by heat, is transformed into a kind of 
air capable of feeding the fire like common air. 
Thus fire hasa double fund of certain subsist- 
ence ; if it consume much air it can also pro- 
duce much by the rarefaction of water, and 
thus repair, in the mass of atmosphere, all the 
quantity it destroyed, ivhile ulteriorly it con- 
verts itself with air into fixed matter in the 
terrestrial substances which it penetrates by its 
heat or by its light. And so, likewise, as 
water is converted into air, or into vapours, as 
volatile as air, by its rarefaction, it is also, 
converted into a solid substance by a kind of 
condensation. Every fluid israreficd by heat and 
condensed by cold. Water follows this com- 
mon law, and condenses as it grows cold. Let 
a p-lass tube be filled three parts full and it will 
descend in proportion as the cold increases, 
l)nt some time before congelation it will ascend 



above the point of three fourths of the height 
of the tube, and increase still more considera- 
bly by being frozen. But if the tube be well 
stopped, and perfectly at rest, the water will 
continue to descend, and will not freeze, al- 
though the degree of cold be six, eight, or teii 
degrees below the freezing point ; congelation, 
therefore, presents, in an inverted manner, the 
same phenomena as inflammation. A heat, 
however great, shut up in a well-closed vessel, 
will not produce inflammation unless touched 
with an inflamed matter ; so, likewise, to what- 
soever degree a fluid is cooled, it will not 
freeze unless it touch something already frozen, 
and this is what happens when the tube is 
shaken or uncorked; the particles of water, 
which are frozen in the external air, or in the 
air contained in the tube, strike the surface of 
the water, and communicate their ice to it. 
In inflammation, the air, at first very much 
rarefied by heat, loses its volume, and fixes it- 
self suddenly. In congelation, water, at first 
condensed by the cold, takes a larger volume, 
and fixes itself likewise, for ice is a solid sub- 
stance, lighter than water, and would preserve 
its solidity if the cold continued the same; and 
I am inclined to believe that wc may attain 
the point of fixing mercury at a less degree 
VOL. X. N of 

90 buffon's 

of coldj by sublimalin^ it info vapours in a 
very cold air; and also that water, which 
only owes its liquidity to. heat, would become 
a substance much more solid and fusible, as 
.it would endure a stronger and a longer time 
the rigour of the cold. 

But without stopping upon this subject, 
that is, without admitting or excluding the 
possibilily of the conversion of the ice into in- 
fusible matter, or fixed and solid earth, let us 
pass on to more extensive views on the modes 
.which Nature makes use of for the transfor- 
mation of water. The most powerful of all and 
the most evident is the animal filter. The 
body of shell-animals, by feeding on the par- 
ticles of water, labours, at the same time, on 
the substance to the point of unnaturalizing it. 
The shell is certainly a terrestrial substance, a 
true stone, from which all the stones called 
calcareous^ and many other matters, derive 
their origin. This shell appears to make the 
constitutive part of the animal it covers, since 
it is perpetuated by generation, for it is on 
thesraall shell-animal just come into existence 
as well as on those which have arrived at their 
full growth ; but this is no less a terrestrial 
substance, formed by the secretion or exuda- 
t^ion of the body, for it increases and thickens 


by rings and layers in proportion as the ani- 
mal grows ; and stony matter often exceeds 
fifty or sixty times the mass of the body whicli 
produces it. hot us, for a moment, reflect on 
the number of the kind of shell-animals, or ra_ 
Iher of those animals with a stony transuda- 
tion ; they, possibly, arc more numerous in the 
sea than (he insect kind are upon earth. Lei 
us afterwards represent their full growth, their 
prodigious multiplication, and the shortness 
of their lives, which we may suppose does 
not excee<l ten years ; let us then consider that 
"we must multiply by fifty or sixty the almost 
imniense number of the individuals of this class 
to form an idea of ail the stonj' matter pro- 
duced in ten years; then that this block must 
be augmented with as many similar blocks as 
there are as many times ten in all the ages 
from the beginning of the world, and by this 
means we shall conceive, that all our coral, 
rocks of calcareous stone, marble, chalk, &c. 
originally proceeded alone from the cast-otf 
coats of those little animals. 

SaltSj bitumeUj oil, and the grease of the 
sea, enter little or none into the composition 
of the shell; neither does the calcareous stone 
contain any of those matters; this stone is, 
therefore, only water hansformed, joined to 
«Dme little portion of vitrifiable earth, and to a 


92 buffon's 

great quantity of fixed air, which may be dis- 
engaged by calcination. This operation pro- 
duces the same effect on the shells taken in the 
sea as upon those drawn out of quarries ; they 
both form lime, with only a little difference in 
their quality. Lime, made with oyster or 
other shells, is weaker than that made with 
marble or hard stone; but the process of Na- 
ture is the same, as are the results of its opera- 
tion. Both shells and stones, lose nearly half 
their weight by the action of fire in calcination; 
the water issues first, after which the fixed air 
is disengaged, and then the fixed water, of 
which these stony substances are composed , re- 
sumes its primitive nature, is elevated into va- 
pours, drove off and rarefied by the fire, so that 
there remains only the most fixed parts of this 
air and water, which, perhaps, are so strongly 
united in themselves, and to the small quantity 
of the fixed earth of the stone, that the fire cannot 
separate them ; the mass, therefore, is reduced 
nearly a half, and would probably be still 
more if submitted to a stronger fire. And what 
appears to me to prove that this matter, driven 
out of the stone by the fire, is nothing else than 
air and water, is the avidity with which cal- 
cined stone sucks up the water given to it, and 
the force with which it draws water from the 
atmosphere. Lime, by exposure either in air 



or water, in a great measure regains the mass{ 
it had lost by calcination ; the water, with the 
air it contains, replaces that which the stone 
contained before. Stone then retakes its first 
nature, for in mixing lime with the remains of 
other stones, a mortar is made which hardens, 
aiid becomes a solid substance, like those from 
which it is composed. 

Thus, then, we see on the one hand all the 
calcareous malters, the origin of which we 
must refer to animals ; and on the other, all the 
combustible matters proceeding from animal 
or vegetable substances; they occupy together 
a great space on the earth ; yet, however great 
their number may be, they only form a small 
part of the terrestrial globe, the principal 
foundation of which, and the greatest quan- 
tity consisis in one matter of the nature of 
glass ; a matter we must look upon as ter- 
restrial element, to the exclusion of all other 
substances, to which it serves as a base, like 
earth, when it forms vegetables by the means, 
or remains of animals, and by the transforma- 
tion of the other elements ; and it is also the 
ulterior term to which we can return or reduce 
them all . 

It appears that the animal filter converts 
water into stone ; the vegetable filtre can also' 
transform it, when all the circumstances are 


94l buffon^s 

found to be the same. The heat of vegetables 
and the organs of life being less powerful (haii 
those of shell animals, the vegetables can pro- 
duce only a small quantity of stones, which 
are frequently found in its fruits ; but it can 
and does convert a great quantity of air, and a 
still greater of water into its substance. It 
may be asserted, without fear of contradiction, 
that the fixed earth it appropriates, and which 
serves as a base to these two elements, does not 
make the hundredth part of its mass; hence, 
the vegetable is almost entirely composed of 
air and water, transformed into wood, or a 
solid substance, which is afterwards reduced 
into earth by combustion and putrefaction. 
The same may be said of animals ; they not 
only fix and transform air and water, but fire^ 
and in a much greater quantity than vege- 
tables. It appears, therefore, to me, that the 
functions of organized bodies are the most 
powerful means made use of by Nature for the 
conversion of the elements. We may regard 
each animal, or vegetable, as a small particular 
centre of heat or fire that appropriates to itself 
the air and water which surround it, assimilates 
hem to vegetate or nourish, and live on the 
productions of the earth, which are themselves 
only air and water previously fixed. It also^ 
appropriates to itself a small quantity of earth , 



and reccivini^ the impressions of liglit, the heat 
of the sun and terrestrial globe, it converts into 
its substance all these different elements; 
works, combines, unites, and opposes them, 
till they have undergone the necessary form 
towards its support of life, and the growth of 
organization, the mold of which once given, 
models every matter it admits, and from inani- 
mate renders it organized. 

Water, which so readily coalesces and enters 
with air into organizcdbodies, unites also with 
some solid matters, such as salts ; audit is often 
by their means that it enters into the com- 
position of minerals. Salt at first appears to 
be only an earth soluble in water, and of a 
sharp flavour, but chemists have perfectly 
discovered, that it principally consists in the 
union of what they term the earthlj/ and the 
aqueous principle. The experijp.ent of the 
nitrous acid, which after combustion leaves 
only a small quantity of earth and water, has 
caused them to think, that salt was composed 
only of these two elements ; yet I think it 
is easily to be demonstrated, that air and fire 
also enter their composition ; since nitre pro- 
duces a great quantity of air in combustion, 
and this fixed air supposes fixed fire which dis- 
engages at the same time : besides all the expla- 
nations given of the dissolution cannot be sup- 

96 buffon's 

ported, and it would be against all analogy, 
that salt should be composed only of these 
two elements, while all other substances are 
composed of four. Hence we must not re- 
ceive literally what those great chemists 
Messrs. Stalil and Macquer have said on this 
subject ; the experiments of Mr. Hales de- 
monstrate, that vitriol and marine salt contain 
much fixed air ; that nitre contains still more, 
even to the eighth of its weight ; and that salt 
of tartar contains still more than these. It 
may, therefore, be asserted that air enters as a 
principle into the composition of all salts ; 
but this does not support the idea that salt is 
the mediate substance between earth and water; 
these two elements enter in different propor- 
tions into the different salts or saline sub- 
stances, whose variety and number are so great, 
as not to be enumerated ; but which, generally 
presented under the denomination of acids and 
alkalis, shews us, that there is in general 
more earth than water in the last, and more 
water than earth in the first. 

Nevertheless, water, although it may be 
intimately mixed with salts, is neither fixed 
nor united there by a sufficient force to 
transform it into a solid matter like calcareous 
stone ; it resides in salt or acid under its pri- 
mitive form, and the best concentrated acid, 



or ihe most deprived of water, which might be 
looked II pon as liquid earlb, only owes its liquir 
dity to the quantity of (he air and fire it con- 
tains; and it is no less certain, tliat they are in- 
debted for their savour to the same principles. 
An experiment which I have frequently tried, 
has fully convinced mo, that alkali is produced 
by fire. Lime made according to <he common 
mode, and put upon the tongue, even before 
slacked by air or water, has a savour which 
indicates the presence of a certain quantity of 
alkali. If the fire be continued^ this lime by 
longer calcination, becomes more poignant ; 
and that drawn from furnaces, where the cal- 
cination has subsisted for five or six months to- 
gether, is still more so. Now this salt was not 
contained in the stone before its calcination ; 
it augmented in proportion to the strength and 
continuance of the fire ; it is therefore evi- 
dent, that it is the immediate product of the 
fire and air, which incorporate in thesubbtance 
during its calcination, and which, by this 
means, are become fixed parts of it, and from 
which they have driven most of the watry 
molecules it before contained . This alone ap- 
peared to me sufficient to pronounce that fire 
is the principal of the formation of the mineral 
alkali ; and we may conclude, by analogy, that 
other alkalis owe their formation to the con- 
voL. X. O stant 


stant beat of the animal and vegetable fronr 
which they are drawn. 

With respect to acids^ although the demon- 
stration of their formation by fire and fixed air, 
is not So Immediate as that of alkalis, yet it 
does not appear less certain. We have proved , 
that nitre and phosphorus draw their origin 
from vegetable and animal matters : that vitriol 
comes from pyrites, sulphur and other combus- 
tibles . It is likewise certain that acids, whether 
vitriolic, nitrous, or phosphoric, always con- 
tain a certain quantity of alkali ; we must, there- 
fore, refer their formation and savour to the 
same principle, and by reducing the varieties of 
both to one of each, bring back all salts to one 
common origin : those which contain most of 
the active principles of air and fire, will necessa- 
rily have the most power and taste. I under- 
stand by power the force with which salts ap- 
pear animated to dissolve other substances. 
Dissolution supposes fluidity, and as it never 
operates between two dry or solid matters, it 
also supposes the principle of fluidity in the dis- 
solvent, that is, fire ; the power of the dissolvent 
will be, therefore, so much the greater, as on 
one part it contains more of this active princi- 
ple; and, on the other hand, its aqueous and 
terrene parts will have more aflinity with those 
of the same kind contained in the substances- 



to dissolve; and, as the degrees ofaffinity vary, 
we must not be surprized at different salts va- 
rying in their action on different substances ; 
their active principle is the same, their dissolv- 
ing power the same ; but they remain without 
exercise when the substance presented repels 
that of the dissolvent, or has no deo^ree of 
affinity with \i ; but the contrary is the case 
when there is sufficient force of affinity to con- 
quer that of the coherence; that is, when the 
active principles, contained in the dissolvent, 
under the form of air and fire, are found more 
powerfully attracted by the substance to be 
dissolved, than they are by the earth and wa- 
ter they contain. Newton is the first who has 
assigned affinities as the causes of chemical 
precipitation ; Stahl adopted this idea and 
transmitted it to all the other chemists ; and it 
appears to be at present universally received 
as a truth. But neither Newton nor Stahl 
saw that all these affinities, so different in ap- 
pearance, are only particular effects of the ge- 
neral force of universal attraction : and, for 
want of this knowledge, their theory cannot 
-be either luminous or complete, because they 
were obliged to suppose as many trivial laws 
of different affinities, as there were different 
phenomena ; instead of which there is in fact 


100 BUFrox's 

only on6 law of affiuityj a law which is pre-, 
cisely the same as that of universal attraction. 
Salts concur in many operations of Nuture 
by the power they have of dissolvhig other sub- 
stances ; for, although it is commonly said^ 
that water dissolves snK, it is easy to be per- 
ceived, that in reality, when there is a dissolu- 
tion, both are active, and may be alike called 
dissolvents. Regarding- salt as only a dissol- 
vent, the body to be dissolved may be either 
liquid or solid; and, provided the parts of the 
salt be sufficiently divided to touch immediate- 
ly those of the other substances, they will act 
and produce all the effects of dissolution, ^y 
this we see how much the action of salts, and 
the action of the element of water which con- 
tains them, must have influence on the com- 
position of mineral matters. Nature may 
produce hy this mode, all that our arts 
produce by that of fire. Time only is require 
ed for salts and water to produce on the most 
compact and hard substances, the most com-^ 
plete division and attenuation of their parts, 
$o as to render them capable of uniting with 
all analagous substances, and to separate from 
all others; but this time, which to Natnre is 
never wanting, is, of all things, that which is 
the most deficient tons : the greatest ofall our 
arts., therefore, is that of abridging time, that 



is, to effect that in one day, which nature takes 
an age to perform. However vain tliis prc- 
icnsioji may appear, we must not entirely re- 
nounce it, for has not man drscovered the 
mode of creating ure, of applying it to his use, 
and by (he means of tliis element (o suddenly 
dissolve those bodies by fusion which would 
require a considerable period by any other 
means ? 

We must not, however, conclude that Na* 
ture really performs by the means of water all 
4hat we do by fire. The decomposition of 
£very substance is ouly to be made by division, 
and the greater this division the more the de- 
.composition will be complete. Fire seems io 
divide as much as possible those matters which 
it fuses ; nevertheless it may be doubted whe- 
ther those which water and acids keep in dis^ 
solution are not still more divided, and the 
Vapours raised by heat contain matters still 
further attenuated, in the bowels of the carth>, 
?then, by the means of the heat it includes, and 
the water which insinuates, there is made an 
infinity of sublimations; distillation , chrys- 
tallizatlons, aggregations, and disjunctions, of 
every kind. By time all substances may be 
compounded and decompounded by these 
means; water may divide and attenuate the 
parts more than fire when it melts them, and 


102 BUFFO n's 

those attenuated parts will join in the same 
manner as those of fused metal unite by cooU 
ing. Crystallization, of whicli the salts have 
given us an idea, is never performed but Avhen 
a substance, being disengaged from every 
other, is much divided and sustained by a 
fluid, which having little or no affinity with it, 
permits it to unite and form by virtue of its 
force of attraction, masses of a figure nearly 
similar to its primitive parts. This operation, 
which supposes all the above circumstances, 
may be done by the intermediate aid of fire as 
well as by that of water, and is often accom- 
plished by the concurrence of both, because 
all this exacts but one division of matter suffi- 
ciently great for its primitive parts to be able 
to form, by uniting figured bodies like them- 
selves. Now fire can bring many substances 
to this state much belter than any other dis- 
solvent, as observation demonstrates to us in 
asbestos, and other productions of fire, whose 
figures are regular, and which must be looked 
upon as true crystallizations. Yet this de- 
gree of division, necessary to crystallization, 
is not the greatest possible, since in this state 
the small parts of matter are still sufficiently 
large to constitute a mass, which like other 
masses, is only obedient to the sole attractive 
force, and the volumes of which, only touch? 
ing in points, cannot acquire the rcsultive 


BUFFO N*S 105 

farce that a much greater division might per- 
form by a more immediate contact, and this 
is what we see happen in eftervescences, where 
at once, heat and light are produced bj the 
mixture of two cold liquors. 

Light, heat, fire, air, water, and salts, are 
steps by which we descend from the top of 
Nature's ladder to its base, which is fixed 
earth . And these are at the same time the 
only principles that we must admit and com- 
bine for the explanation of all phenomena. 
These principles are real, independently of 
all hypotheses and all method, as are also 
their conversion and transformation, which 
are demonstrated by experience. It is the 
same with the element of earth, it can convert 
itself by volatilizing and taking the form of 
the other elements, as those take that of earth 
in fixing ; it, therefore, appears quite useless 
to seek for a substance of pure earth in terres- 
trial matters. The transparent lustre of the 
diamond dazzled the sight of our chemists, 
when they considered that stone as a pure ele- 
mentary fire ; they might have said with as 
much foundation, that it is pure water, all the 
parts of which are fixed to compose a solid 
diaphanous substance. When we would de- 
fine Nature, the large masses should alone be 
considered, and those elements have been well 
t^ken notice of by even the most ancient philo- 

104 BUFFO n's 

soplicrs. Tbc sun, atmosphere, earlh, sea, &c. 
are all great masses on which they establisiied 
all their conclusions ; and ifthere ever had ex- 
isted a planet of phlogiston, an atmosphere 
of alkali, an ocean of acid, or a mountain of 
diamonds, such might have been looked upon 
as the general and real principles of all bodies, 
but they are only particular substances, pro- 
duced, like all the rest, by the combinations 
of true elements • and ideas to the contrary 
"vvould never have been started but upon the 
supposition that the earth was neither more 
simple nor less convertible than either of the 
other elements. 

In the great mass of solid matter^ which the 
earth represents, the superficial is the least 
pure. All the matter deposited by the sea, in 
form of sediment, all stones produced by shell- 
animals, all substances composed by the com- 
binations of the waste of tlic animal or vege- 
table kingdom, and all those which have beea 
changed by the fires of volcanos, or subli- 
mated by the internal heat of tlie globe, are 
mixed and transformed substances ; and al- 
though they compose great masses they do not 
clearly represent to us the element of earlh. 
They are vitrifiable matters, whose mass must be 
Considered as 100,000 limes more considerable 
than all those other substances, which should 
be regarded as the true basis of this element- 


It is front this common foundation that all 
other substances have derived the origin of 
their solidity, for all fixed matter, however 
much decomposed, subsides finally into glass 
by the sole action of fire : it resumes its first na- 
ture, when dis«ngaged from the fluid, or vola- 
tile matters, which were united with it ; and 
this glass, or virtreous matter, which compo- 
ses the mass of our globe^ represents so much 
the better the element of earth j as it has nei- 
ther colour, smell, taste, liquidity, nor fluidity, 
qualities which all proceed from the other ele- 
ments, or belong to them* 

If glass be not precisely the element of earth, 
it is at least the most ancient substance of it ; 
metals are more recent, and less dignified ; 
and most other minerals form within our sight. 
Nature produces glass only in the particular 
focus of its volcanos, whereas every day she 
forms other substances by the combination 
of glass with the other elements. If v/e would 
form to ourselves a just idea of her formation 
of the globe, we must first consider her proces- 
ses, which demonstrate that it has been melted 
or liquefied by fire ; tliat from this iramenss 
heat it successively passed to its present de- 
cree ; that in the first moments, ^\here its sur- 
face began to take conbistencCi inequalities 
YOL. X. P must 

lOG BUFFO w'* 

must be formed, sucli as we see on the surface 
of racUed matters grown cold : that the high- 
est mountains, all composed of vitrifiable 
matters, existed and take their date from that 
moment, vvhich is also that of the seperation of 
the great masses of air, water, and earth ; that 
afterwards, during the long space of lime 
which the diminution of the heat of the globe 
to the point of present temperature supposes, 
there were made in these mountains, which. 
T\ere tlie parts most exposed io the action 
of external causes, an inftnity of fusions, sub-» 
limatioris, aggregations, and transformations, 
by the fire of the sun, and all the o her causes 
vhich this great heat rendered more active^ 
than they at present are, and that consequently 
we must refer back to this date the format iort 
of metals and minerals which we find in great 
masses, and in thick and continued veins. The 
violent fire of inflamed earth, after having 
raised up and reduced into vapours all that 
was volatile, after having driven off from its 
internal parts the matters which compose the 
atmosphere and the sea, and at the same time 
sublimated all the least fixed parts of the earth, 
raised them up and deposited them in every 
void space, in all the cavities which formed on 
the surface in proportion as it cooled ; this, 
then, is the origin and the gradation of the 



sitttntioh nhd formation of vitrifinble matters 
■which fire lias dividct], formed andsubUmated 

After this first establishment (and ^vhich 
still subsists) of vitrifiable matters and minerals 
into a gt-eat mnss, whicli can be attributed to 
the action of fir(3 alone, water which till then 
formed with Air only a vast volume of vapours, 
begiin to take its present slate ; it collected 
and covered the greatest part of the surface of 
the earth, on which, finding itself agitated 
by a cohtiliualflux aud reflirx, by the action bf 
^Viiids arid heat, it began to act on thfe works 
of fire: it changed, by degrees, the superfici^ 
of vitrifiable matters ; it transported the wrecks 
rtnd deposited them in the form of sediments ; it 
nourished shell-ahiraals,it collected their shells, 
produced calcareous stones, formed hills and 
mountains, which becoming afterwards dry, 
received in their cavities all the mineral mat- 
ters they could dissolve or contain. 

To establish a general theory on the for- 
mation of Minerals, we must begin then by 
distinguishing with the greatest attention, first, 
those which have been prod need by the pri- 
tnttive fire of the earth while it was burning 
witli heat ; secondly, those which have been 
farmed (torn the waste ofthe first by the means 
pf water; and thirdly, those which in vol- 


103 buffon's 

canosj or other subsequent conflagration^ 
have a second time undergone the proof of a 
violent heat. These three objects arc very 
distinct, and comprehend all the mineral 
kingdom; by not losing sight of them, and by 
connecting each substance, we pan scarcely be 
deceived in its origin, or even in the degrees 
of its formation. All minerals which are found 
in masses, or large veins in our high moun- 
tains, must be referred to the sublimation of 
the primitive fire ; all those which are found 
in small ramifactions, in threads or in vegeta- 
tions, have been formed only from the waste 
of the first hurried away by the stillation of 
■waters. We are evidently convinced of this, 
hy comparing the matter of the iron mines 
of Sweden with that of our own. These 
are the immediate work of water, and we see 
them formed before our eyes ; they are not at- 
tracted by the load stone ; they do not contain 
any sulphur,and are found only dispersed in the 
earth ; the restare all more or less sulphureous, 
all attracted by the load stone, which alone sup- 
poses that they have undergone the action of 
fire ; they are disposed in great, liard, and solid 
masses: and their substance is mixed with a 
quantity of asbestos, another index of the 
action of fire. Iti^the same with other metals: 
their ancient foundation comes from fire, and 



all their great masses have been united by its 
action ; but all their crystallizations, vegeta= 
tions, granulations, &c. are due to the second- 
ary causes, in which water is the primary 



I CAUSED ten bullets to be made of forged 
and beaten iron ; the first, of half-inch diame- 
ter; the second, of an inch; and soon pro- 
gressively to five inches : and as all the bullets 
were made of iron of the same forg^e, their 
weights were found nearly proportionable to 
their volumes. 

The bullet of half an inch weighed 190 
gr(iins, Paris weight ; that of an inch, 1522 
grains; that of an inch and a half, bl36 
grains; that of two inches, 12173 grains; 
that of two inches and an half, 23781 grains ; 
that of three inches, 41085 grains ; that of 
three inches and a half, 65':^5ii grains; that of 
four inches, 97S88 grains ; that of ftnir inches 


IK) buffok's 

a^d an half, i^8179 grains; and that of five 
inches, 190211 grains. All these weights 
were taken with very good scales, and those 
bnllets which were found too heavy, were 

While these bullets were making, the ther- 
mometer exposed to the open air was at the 
freezing point, or some degrees below ; but \n 
the pit where the bullets w^ere suffered (o cool, 
the thermonicler was nearly ten degrees above 
that point ; that is to say, to the degree of tem- 
perature of the pits of the observatory, and it 
is this defirree which! liave here taken for that 
of tlie actual temperature of the earth. To 
know the exact moment of their cooling to 
this actual temperature, other bullets of the 
same matters, diameters, and not heated, were 
juadc use of for comparison, and which were 
felt at the same time as the others. By the ira* 
mediate touch of the hand, or two hands, on 
the two bullets, we could judge of the moment 
yfhcn they were equally cold; and as the 
greater or less smoothness or roughness of 
bodies makes a great difference to the touch ; 
(a smooth body, w^hether hot or cold, ap- 
pearing much more so than a rough body, 
even of the same matter, although they are 
both equally so) I took care that the cold bul- 



lets were rou^gh, and like those \vhich bad 
been heated, \^ hose surfaces w<ire sprinkled over 
with little eminences produced by the fire. 


I. The bullet of half an inch was healed 
"white in two minutes, cooled so as to be heUl 
in the hand in V2y and to the actual tcmpem- 
ture in 39 minutes. 

II. That of an inch, heated white in fi\re 
minutes and a half, cooled so as to be held in 
the hand, in 35^ minutes, and to the actual 
teiuperature in one hour and 2,5 minutes, 

III. That of an inch and an half, heated 
white in nine minutes, cooled so as to be hekl 
in the hand in 5S minutes, and to the actaal 
temperature in two hours and 35 minutes. 

IV. That of two inches heated white in 13 
minutes, cooled so as to be held in the hand 
in one hour 20 minutes, and to the actual 
temperature in three hours 16 minutes. 

V. That bullet of two inches and an half 
heated white in 16 minutes, cooled so as to be 
held in the hand in one hour 42 minutes, and 
to the actual temperature in four hours SO 

VI. That bullet of three inches heated white^ 
in 191 minutes, cooled so as to be held in the 
hand in t ^o hours seven minutes, and to (he 
actual ^empcratuie in five hours eiijht minutes, 


112 BUFFO n's 

VII. Tlmt of three inched aHcl a half beafecl 
\vhite in 2S| minutes, cooled so as to be held 
in the hand in two hours 36 minutes, and to 
theactual temperature in five hours 56 minutes. 

VIII. That of four inches heated white in 
27 minutes and a half, cooled so as to be 
held in the hand in lliree hours two minutes, 
and to the actual temperature in six hours 55 

IX. That of four inches and a half heated 
white in SI minutes, cooled so as to be held in 
the hand in three hours and 25 minutes, and 
to the actual temperature in seven hours 46 

X. That of five inches heated white in S4 
minutes, cooledj so as to be held in the hand, 
in three hours 52 minutes, and to the actual 
temperature in eight hotirs 42 minutes. 

The most constant difference that can be 
taken between each of the terms which express 
the time of cooling, from the instant the bullets 
were drawn from the fire, to that when we can 
touch them unhurt, is fouild to be about 24 
minutes, for, by supposing each term to in- 
crease 24, we shall have 12, 36, 60, 84, 108, 
IS2, J56, 180,204, 228 minutes. And the 
continuation of the real time of these coolings 
are, 12, 351, 58, 80, 102, 127, 156, 182, 205,. 
232 minutes, which approach the first as 



nearly as experiment can approach calcula- 

So, likewise, the most constant difference to 
be found between each of the terms of coolins: 
to actual temperature is found to be 5i minutes, 
for by .supposing each term to increase 54, we 
shall have 3>J, 93, 147, 201, 255, S09, 363, 
417, 471, 5:5 minutes, and the continuation 
of the real lime of this cooling is found, by the 
preceding experiments, to be 39, 93, 145, 196j 
248, 308, 356, 415, 466, 522 minutes, which 
approaches also nearest to the first* 

I made the like experiments upon the same 
bullets twice or thrice, but found I could only 
rely on the first, because each time the bullets 
were heated they lost a considerable part of 
their weight, which was occasioned not only 
by the falling off of the parts of the surface 
reduced into scoria, but also by a kind of dry- 
ing, or internal calcination, which diminishes 
the weight of the constituent parts, insomuch 
that it appears a strong fire renders the iron 
specifically lighter each time it is heated; and 
I have found, by subsequent experiments, tfiat 
this diminution of weight varies much, ac- 
cording to the different quality of the iron. 
Experience has also confirmed me in the opi- 
nion, that the duration of heat, or the time 
VOL. x» Q taken 

IM buffon's 

taken up in cooling of iron, is not in a smaller, 
as stated in a passage of Newton, but in a 
larger ratio than that of the diameter. 

Now if we would enquire how long it would 
require for a globe as large as the earth to cool, 
"we should find, after the preceding experi- 
ments, that instead of 50,000 jears, which 
Newton assigns for the earth to cool to the pre- 
sent temperature, it would take 42,964 years, 
221 days, to cool only to the point where it 
would cease to burn, and 86,667 years and 132 
days, to cool to the present temperature. 

It might only be supposed, that the refrige- 
ration of the earth should be considerably in- 
creased, because we imagine that refrigeration 
is performed by the contact of the air, and 
that there is a great difference between the 
time of refrigeration in the air and in vacuo; 
and supposing that the earth and air cool in 
the same time in vacuo, this surplus of tim« 
should be reckoned. But, in fact, this dif- 
ference of time is very inconsiderable, for 
though the density of the medium, in which 
a body cools, makes something on the dura- 
tion of the refrigeration, yet this effect is much 
less than might he imagined, since in mercury, 
which is eleven thousand times denser than air, 
it is only requisite to plunge bodies into it 



about nirre times as often as is required to pro- 
duce the same refrigeration in air. The prin- 
cipal cause of refrigeration is not, therefore, 
the contact of the ambient medium, but the 
expansive force which animates the parts of 
heat and fire, which drives them out of the 
bodies wherein they reside, and impels them 
directly from the centre to the circumference. 
By comparing the time employed in the 
preceding experiments to heat the iron globes, 
with that requisite to co(A them, ^^e find that 
they may be heated till they become white in 
one sixth part and a half of the time they take 
to cool, so as to be held in the hand, and about 
one fifteenth and a half of that to cool to ac- 
tual temperature, so that there is a great error 
in the estimate which Newton made on the 
heat communicated by the sun to the comet of 
1680, for that comet having been exposed to 
the violent heat of the sun but a short time, 
could receive it only in proportion thereto, 
and not only in so great a degree as that au- 
thor supposes. Indeed, in the passage alluded 
to, he considers the heat of red-hot iron much 
less than in fact it is, and he himself states it 
to be, in a Memoir, entitled, The Scale of 
Heat, published in the Philosophical Trans- 
actions of 1701, which was many years after 

116 buffon's 

the publication of h'ls prwcjples. We see in 
that excellent Memoir, which includes the 
germ of all the ideas on which thermometers 
have since been constructed; that Newton, 
after very exact experiments, makes the heat of 
boiling water to be three times greater than 
that of the sun in the height of summer ; that 
of melted tin, six times greater ; that of melted 
lead, eight times; that of melted rogulus, 
twelve times; and that of a common culinary 
fire, sixteen or seventeen times ; hence we may 
conclude, that the heat of iron, when heated 
so as to become white, is still greater, since it 
requires a fire continually animated by tho 
bellows to heat it to that degree. Newton 
seems to be sensible of this, for he says, that 
the heat of iron in that state seems to be seven 
or eight times greater than that of boiling 
water. This diminishes lialfthe heat of this 
comet, compared to that of liot iron. 

But this diminution, which is only relative, 
is nothing in itself, nor nothing in comparison 
with that real and very great diminution which 
results from our first consideration. For the 
comet to have received this heat a thousand 
times greater than that of red-hot iron, it must 
have remained a very long time in the vicinity 
©f the sun, whereas it only passed very rapidly 



at a small distance. It was on the Stli of De- 
cember, 16S0, at ~oo distance from the earth 
to the centre of the sun ; but 24 hours before, 
and as many after, it was at a distance six 
times greater, and where the heat was consc" 
quently 36 times less. 

To know then the quantity of this heat com- 
municated to the comet by the sun, we here 
find how we should make this estimation tole- 
rably just, and, at ihc same time, make tlie 
comparison with hot iron by the means of my 

We shall suppose, as a fact, that this comet 
took up 666 hours to descend from the point 
where it then was, and which point was at an 
equal distance as the earth is from the sun, 
consequently it received an equal heat to what 
the earth receives from that luminary, and 
which I here take for unity ; we shall likewise 
suppose that the comet took 666 hours more 
to ascend from the lowest point of its perihe- 
lium to this same distance; and supposing 
also its motion uniform, we shall perceive, 
that the comet being at the lowest point of its 
perihelium, that is, to yoVo ^^ the distance 
from the earth to the sun, the heat it received 
in that motion was 27,766 times greater than 
that the earth receives. By giving to this 
Hiotion a duration of 80 minutes, viz. 40 for its 


118 UUi'FON's 

descent, and 40 for its ascent, we sball have, 
at 6 distance, 27,776 heat duvini^ 80 minutes 
at 7 distance 20,408 heat also during 80 mi- 
nutes, and at S distance 13,625 heat during 
80 minutes, and thus, successively, to the 
distance of 1000, where the heat is one. By 
summing up the quantity of heat at each dis- 
tance we shall find ^63,110 to be the total of 
the heat the comet has received from the sun, 
as much in descending as in ascending, which 
must be multiplied by the time, that is, by 
four thirds of an hour; we shall then have 
484,547, which divided by 2,000 represents 
the solid heat the earth received in this time 
of 1332 hours, since the distance is always 
1,300, and the heat always equals one. Thus 
we sliall have 242, aV^ for the heat the comet 
received more than the earth during the wliole 
time of its perihelium instead of 28,000, as 
Newton supposed it, because he took only 
the extreme point, and paid no attention to the 
very small duration of time. And this heat 
must still be diminished 242,^^, because the 
comet ran, by its acceleration, as much more 
way in the same as it was nearer the sun. 
But by neglecting this diminution, and ad- 
mitting that the comet received a heat nearly 
242 times greater than that of our summer's 
sun, and, consequently 177 times greater ^^^an 



fhat of hot iron, according to Newton's esti- 
mation, or only ten minutes greater according 
to this estimation ; it must be supposed, that 
give a heat ten times greater than that of red 
Lot iron, it required ten times more time ; that 
is to say, 1332; consequently, we may compare 
the comet to a globe of iron heated by a 
forge fire for 13320 hours, to lieat it to a 

Now we find by calculation from ray expe- 
riments, that with a forge fire, we can heat to a 
whiteness a globe whose diameter is 228342 J 
inches in 799200 minutes, and, consequently, 
the whole mass of the comet to be heated to the 
point of iron to a whiteness, during the short 
time it was exposed to the heat of the sun, could 
only be 2233421 inches in diameter ; and even 
then it must have been struck on all sides, and 
at the same time, by the light of the sun. 
Thus comets, when they approach the sun, do 
Jiot receive an immense nor a very durable 
heat, as Newton says, and as we at the first 
view might be inclined to believe. Their stay 
is so short in the vicinity of the sun, that their 
masses have not time to be heated, and besides 
only part of their surface is exposed to it ; 
this part is burnt by the extreme heat, which 


120 buffom's 

by calcining and volatilizing the matter of this 
surfkce, drives it outwardly in vapours and 
dust from the opposite side to the sun ; and 
what is called the tail of the comet, is nothing 
else than the light of the sun rendered visible, 
as in a dark room, by those atoms which the 
heat lengthens as it is more violent. 

But another consideration very different and 
infinitely more important, is, that to apply 
the result of our experiments and calculation 
to the comet and earth, we must suppose them 
composed of matters which would demand as 
much time as iron to cool: whereas, in reality, 
the principal matters of which the terrestrial 
globe is composed, such as clay, stones, &c. 
cannot possibly take so long. 

To satisfy myself on this point, I caused 
globes of clay and marl to be made, and having 
heated them at the same forge until white, I 
found that the clay balls of two inches, cooled 
inSS minutes so as to be held in thehand ; those 
of two inches and an half, in 48 minutes ; and 
those of three inches, in 60 minutes ; w liich 
being compared with tlie time of the refri- 
geration of iron bullets of the same diameters, 
give 38 to 80 for two inches, 48 to 102 for 
two inches and a half, and 60 to 127 for 



three ihclies ; so that only half the time is re- 
quired for the refrigeration of clay, to what is 
necessary for iron. 

I found also, that lumps of clay, or marl^ 
of two inches, refrigerated so as to be held in 
the hand in 45 minutes ; those of two inches 
and a half in 58 ; and those of three inches in 
75, which being compared with the time of 
refrigeration of iron bullets of the same dia- 
meters, gives 46 to SO for two inches, 58 to 
102 for two inches and a half, and 75 to 127 
for three inches, which nearly form the ratio 
of 9 to 5 ; so that for the refrigeration of 
clay, more than half the time is required than 
for iron. 

It is necessary to observe, that globes of clay 
iieated white, lost more of their weight than 
iron bullets, even to the ninth or tenth part of 
their weight : whereas marl heated in the same 
jfire, lost scarcely any thing, although the 
whole surface was covered over with scales, 
and reduced into glass. As this appeared sin- 
gular, I repeated the experiment several times, 
increasing the fire, and continuing it longer 
than for iron ; and although it scarcely requir- 
ed a third of the time to redden marl, to what 
it did to redden iron, I kept them in the fire 
thrice as long as was requisite, io sec if they 
would lose more, but I found very trifling di- 
TOL. X. R miziulions ; 

129 BUFFO N*S 

mwiutions ; for fhe globe of two inches lieated 
foe eight minutes, which weighed seven ounces^ 
two drachms, and thirty grains, before it was 
put in tlie fire, lost only forty-one grains, 
which docs not make a hundredth part of its 
weight ; and that of three in ches,wliich weighed 
twenly-four ounces, five drachms, and thirteen 
grains, having been heated by the fire for 
eighteen minutes, that is nearlj^ as much as 
iron^, l©st only seventy-eight grains, which 
does riot make the hundredth and eighty-first 
part of its weight. These losses are so trifling, 
that it may be looked upon, in general, as cer** 
taialhat pure clay loses nothing of its weight 
in the fire ; for those trifling diminutions were 
certainly occasioned by the ferruginous parts 
wliich were found in the clay, and which were 
in part destroyed by the fire. It is also worthy" 
of observation, that the duration of heat in 
difierenLmatters exposed to the same fire for an 
equal time, is always in the same proijortion, 
whether tlie degree of heat begreatt?ror smaller. 
, I have made similar experiments on globes 
of maib)e, stone, lead^ and tin, by a heat only 
strong enough to melt tin, and I found, that 
iron refrigerated in eighteen minutes, so as to 
be able to liold it in the hand, marble refri- 
gerated to the same degree in twelve minutes, 
stone iu eleven, lead in nine, and tin in eiglit. 



it is not, therefore, in proportion to their den- 
tsitj, as is commonly supposed, that bodies 
receive and lose more or less heat, but iti an 
inverse ratio of their solidity; that is, of their 
greater or lesser non JIuid'df/ ; so that, by the 
game heat, less time is requisite to Iteiit or cool 
the most dense fluid. 

To prevent the suspicion of vainly dwelling 
upon assertion, I think it necessary to remark 
iipon what foundation I build this theory ; I 
have found that bodies which should heat in 
ratio of their diameters, could be only those 
which were perfectly permeable to heat, and 
would heat or cool in the same time ; hence, 
I concluded that fluids, whose par(s are only 
held together by a slight connection, might 
approach nearer to this perfect permeability 
than solids, whose parts have more cohesion. 
In consequence of this, I made ex[3eriments, 
by which I found, that with the same heat all 
fluids, however dense they might be, heat and 
cool more readily than any solids, howev»er 
light, so that mercury, for example, heats 
much more readily than wood, although it 
be fifteen or sixteen times more dense. 

This made me perceive that the progress of 
heat in bodies cannot, in any case, be made 
relatively io their density ; and I have found 


124 buffon's 

by experience, that this progress, sis well in 
solids as fluids, is made rather by reason of 
their fluidity, or in an inverse ratio of their so- 
lidity. I mean by solidili/ the quality oppo- 
site to fluidity ; and I say, that it is in an in- 
verse ratio of this quality that the progress 
of heat is made in both bodies ; and that they 
lieat or cool so much the faster as they are the 
more fluid, and so much the slower as thoy arc 
more solid, every otlier circumstance being 

To prove that solidity, taken in this sense, 
is perfectly independent of density, I have 
found, by experience, that the most or least 
dense matters, heat or cool more readily than 
other more or less dense matters, for example, 
gold or lead, which are much more dense than 
iron and copper, heat and cool much quicker ; 
while tin and marble, which are not so dense, 
heat and cool much faster than iron and cop- 
per ; and there arc likewise many other mat- 
ters which come under the same description ; 
so that density is in no manner relative to the 
scale of the progress of heat in solid bodies. 

It is likewise the same in fluids, for I have 
observed, that quicksilver, which is thirteen or 
fourteen times more dense than water, never- 
theless heats and cools in less time than water ; 



and spirit of wine, which is less dense than 
water, heats and cools much quicker ; so that 
generally the progress of heat in bodies, as well 
witli regard to tlie ingress as egress, has no 
affinity with their density, and is principally 
made in the ratio of their fluitlity, by extend- 
ing the fluidity to a solid ; from hence I con- 
cluded, that wc should know thereat degree of 
fluidity in bodies, by heating them to the same 
heat ; for their fluidity would be in a like ratio 
as that of the time during which they would 
receive and lose this heat ; and that it would 
be the same with solid bodies. They will bo 
so much the more solid, that is tosay, so much 
the more nonjluids^ as they require more time 
to receive and lose this heat, and that almost 
generally to what I presume; for I have al- 
ready tried these experiments on a gr^at num- 
ber of different matters, and from them I have 
made a table, which I have endeavoured to 
render as complete and exact as possible. 

I caused several globes to be made of an 
inch diameter witli the greatest possible pre- 
cision, from the following matters, which 
nearly represent the Mineral kingdom. 

M. Tillet, of the Academy of Sciences, 
made the globe of refined gold at my particu- 

i2Q buffon's 

lar request, and the whole of tjiem weighed 
as follows : 

oz. d. gr. 

jGoM - - J 6 2 17 

I.ead - - - 3 6 28 

Pure silver - - 3 3 22 

Bismuth - - - 3 3 

€opper-red - - 2 7 56 

Iron . - - 2 5 10 

Tin - - - 2 3 48 

Antimony melted, and which had 

small cavities on its surface 2 1 34 

Fine - - - 2 12 

Emery - - - 1 2 24f 

White marble - - 1 25 

Pure clay - - 7 24 

Marble common of Montbard 7 20 

White gypsum, improperly called 

Alabaster - - 6 3Q 

Calcareous white stone of the quarry 

of Aiiicres, near Dijon - 6 6 6 
Rock chry&tal : it was a little too 
small, and had many defects. I 
presume that without them it 

would have weighed - 6 22 

Common glass - - 6 21 


OZ. ( 

d. gr. 
6 16 
5 9 


5 2i 
4 49 


Pure earth, very dry 


Porcelain of the Court de Laura- 

White chalk 
Cherry wood, i^feicli although lighter 
than most other woods, is that 
which takes in the least fire 1 59 
1 must here observe, that a positive conclii" 
sion must not be made of the exact specific 
weight of each matter from the preceding 
table, for notwithstanding t lie precaution thai 
was taken to render the globes equal, yet, as 
I was obliged to employ different workmen ^ 
some were too large, and others too small. 
Those which were more than an inch diameter 
were diminished, but those of rock chrystal, 
glass and porcelain, which were rather too 
small, we suffered to remain, and only rejected 
those of agate, jasper, and porphyry, which 
were sensibly so. This precision in size was 
however not absolutely necessary, for it could 
very little alter the result of my experiments. 
Previously to ordering these globes, I exposed 
to a like degree of fire, a square mass of iron^ 
and another of lead of two inches diameter,and 
found, by reiterated essays, that lead lieated 


123 bttffon's 

and cooled in much less time tlian iron. I made 
the same experiment on red copperj and that 
TCt]uircd more time to heat and cool than lead, 
and less than iron. So that of these three mat- 
ters, iron appeared the least accessible to hcaf, 
and, at the same time, that Avhich retained 
it the longest. From which I learn that the 
law of the progress of heat in bodies was not 
proportionable to their density, since lead, 
which is more dense than iron or copper, ne- 
vertheless heats and cools in less time than 
either. As this object appeared important, I 
was induced to have these globes made, and to 
be more perfectly satisfied of the progress of 
heat in a great number of different matters, I 
always placed the globes at an inch distance 
from each other, before the same fire, or in the 
same oven, 2, 3, 4, or 5, together w ith a globe 
of tin in the midst of them. In most of my ex- 
periments I suffered them to be exposed to the 
same active fire till the globe of tin began to 
melt, and at that instant they were all remov- 
ed, and placed on a table in small cases. I 
suffered them to cool without moving, often 
trying whether I could touch them, and the 
moment they left offburning,and I could hold 
them in my hands half a second, I marked the 
time which had passed since I drew them from 



the fire. I afterwards suflfered them to cool to 
the actual temperature, of whicli I endeavoured 
to judge by means of touching other small 
globes of the same matters that had not been 
heated. Of all the matters which I put to the 
trial, there was only sulphur which melted ina 
less degree of heat than tin, and notwithstand- 
ing its disagreeeble smell I should have taken 
it for a term of comparison, but being a brittle 
matter which diminishes by friction, I pre- 
ferred tin, although it required nearly double 
the heat to melt. 

Having heated together bullets of iron, cop- 
per, lead, tin, gres, arid Moiitbard marble, 
they cooled in the following order : 

So as to be held in the hand for 

To actual temperature. 

half a second. 



Tin in - - 6| 




- 16 

Lead in - - S 




- 17 

Gresin - - D 




- 19 

Common marble in 10 




- 21 

Copper in - l\\ 




- 30 

Iron in - - IS 




- SS 

l^y a second experiment with a fiercer fire, 
sufficient to melt the tin bullet, the five others 
cooled . 
VOL. X, S So 



So as to he 

hddinthe hand. 


' actual tefii pet afar 




Lead in 








Gres in 
































By a third experiment, with a less degree 
of fire than the preceding, the same bullets 
with a fresh tin buUetj cooled in the following 

So as to be held in 

the hand. 

To actual 

' temperature. 



Tin in 

'• n 




- 25 

Lead in 

' n 




- 25 

Gres in 

- lOi 




. 37 

Common marble 12 




- S9 


- 14 




- 44 


- 17 




- 50 

From these experiments, which I made with 
as much precision as possible, we may con- 
clude, first, that the time of refrigeration of 
iron, so as to be held in the hand, is to that of 
copper : : 53| : 45, and so to the point of 
temperature : : 142 : 125. 

2dly, That the time of refrigeration of iron, 
so as to be held in the hand, is to that of the 
first refrigeration of common marble : : 5S| : 
35f and their entire refrigeration « : 142 : 110. 



Sdly, that the time of Tefrigeration of iron, 
to that of gres, so as to be held in the hand, is 
: : 53| : S2 and : : 142 : 102^, for their en- 
tire refrigeration. 

4thly, That the time of refrigeration of 
iron <o that of lead, so as to be held in the 
hand, is : : 531 ' 27 and li^ ; QU for their 
entire re fri operation. 

In an oven hot enough to melt tin, although 
all the coals and cinders were drawn out, I 
placed, on a piece of iron wire, five bullets, 
distant from one another about nine lines, after 
which the oven was shut, and haying drawn 
them out, in about 18 minutes they cooled, 

So as to be hdd in 

the hand. 

To actual 




Melted tin in 

- 8 




- 24 

Silver in 

- 14 




- 40 

Gold in 

- 15 




- 46 

Copper in - 

.- \6\ 




- 50 

Iron in 

- 18 




. 56 

In the same oven, but with a slower heat, 
the same bullets with an other bullet of tin, 

So as to be held in 

the hand. 

To actual temperature. 



Tin in 

- 7 

In - - - 20 

Silver in - 

- 11 

In - - - 56 




Gold in 

- \2\ 

In - 

- - 40 

Copper in - 

' 14 

In - 

- - 43 

Iron in 

- 16i 

In - . 

■ - 47 

In thesameoven, but wiilia still less degree 

of heat, the 

same bullets cooled, 

So as to ie held in tbs hand. 

To attuai 

I temferatut;e. 



1 m in 

- 6 

hi . 

- - 17 

Silver in - 

- 9 

In - 

- - 26 

Gold in . 

- 91 

In - 

- - 28 

Copper in 

. 10 

In - 

- - 31 

Iron in 

- 11 

In - 

- - 35 

Having placed in the same oven five other 
bullets, placed the same and separated from 
each other, their refrigei*ation was in the fol- 
lowing pioporlions. 

^ So as to be held in 



To Mctual 

' tempi 



Antimony in 








Bismuth in 








Lead in 








jL'mic in 








Emery in 








In the same oven, and in the same manner, 
another nullet of Bismuth was placed, with 
six oilier bullets, which cooled. 

So as to be held in the band. To actual temperature. 

Min. Min 

Anii^iiony in - 6 In . - - - 23 
Bismuth in - 6 In - - - 25 



. - - - 28 

.... so 

. - - - 32 
. - - - 34 
- - r - 39 

There was put in the same oven a bullet of 
glass, another of tin, one of copper, and one 
of iron, and they cooled, 

Lead in 

■ 7i 


Silver in f 

- 9f 


Zinc in 

- lOi 


Gold in 

- Hi 


Emery in - 

- m 


S« ai to be held in the hand. 

To actual temperature. 



Tin in - - 8 


- - - . 27 

Glass in - - 8^ 


- - - - 22 

Copper in - - 14 


- - - - 42 

Iron in - - 16 


- . - - 50 

Bullets of gold, glass, porcelain, gypsum, 
and grcs, were heated together, and cooled, 

So as to be held in the band. 


actual temperature. 



Gypsum in - - 8 


- - 

- - 24 

Porcelain in- - Sf 



- - 25 

Glass in - - 2 


- - 

- - 26 

Gres in - - 10 



- - 32 

Gold in - - 141 


- - 

- - 45 

Bullets of silver, common marble, hard 

stone, white marble, and soft calcareous stone 

of Aniercs, near Dijon, were heated like the 

former, and cooled, 


134: BUFFON S 

So as to be held in the hand. To 





Syoft calcareous slone in 8 



- 25 

Hard stone in - - - 10 



- 34 

Common marble in - 11 



- 35 

White marble in - - 12 



- 36 

Silver in - - - - 13f 



- 40 

The whole of these experiments were made 
-vvitb the utmost care and attention, not only 
by myself but in the presence of several per- 
soiis, who also endeavoured to judge of the 
first degree of temperature by holding the bul- 
lets for half a iecond in their hands, and the 
relations of which are more exact than those 
of the actual temperature, because that being 
variable the result must sometimes vary also. 

With a view to avoid that proxility which 
would necessarily attend the continual repeti- 
tion in a comparative statement of the refrige- 
ration of these diflerent bodies, we have con- 
nected them iii a general table, and taking 
10,000 for the st^mdard of comparison, their 
diflfences mny be seen at one vicAV. 





J^elations of different Mineral Substances', 

IRON^ Tvith 

First Entir* 
■Refrig. Refrig-, 

-Emery - . 10000 fo 9117— 9020 

popper - to 8512—8702 

yP^d - - to8J60— 8148 

^i^^c - - to 7653—6020 

Silver . - . . to 7619— 7423 

Marble White - to 6774—6704 

Marble common - to 66.36— 6746 

Stone calcareous hard • to 6617 6274 

J.^»*-'s - - -to 5596— 6926 

y^ass - - to D^76^bS05 

}.\^^^ - - to 5143—6482 

^^» - - to 4898— 4921 

Mone calcareous soft - — — to 4194—4659 

^l^y - - to 4198—4490 

^|s«iuth - . , fo 3580-4081 

^"alk - . to 3086-3878 

Cxum - - to 2325— 2817 

V\ ood - . . to 1890—1594 

I umice-stonc - to 1627 1268 


iBQ BVTFoas 

EMERY, Tvilli 

First Entire 
Refrig. Refrig. 

Copper - - 10000 to 8519— 8148 

Gold - - - to 8513—8560 

Zinc - - to 8S90— 7693 


Silver - - to 7778— 7895 

S(one calcareous hard - to 7304 — 6963 

Gres - - to 6552— 6517 

Glass • - to 5862— 5506 

Lead - - to 5718— 6643 

Zinc - - to 5658—6000 

Clay - - 10 5185—5185 

Bismuth - - to 4949— 6060 

Antimony - to 4540— 5S27 

Oker - - to 4259— 3827 

Chalk - - to 3684— 4105 

Gypsum''"^- - to 2368—2947 

Wood ^ - - to 1552—3146 

COPPER, Avith 

Gold - - 10000 to 9136—9194 

Zinc - - to 8571— 9250 


Silver - - to 8395— 7823 

Marble common - to 7639—8019 

Gres - . - to 7333— 8160 

Glass - - to 6667— 6567 

Lead - - to 61 79— 7367 




First Entire 
Re frig 

Tin - 10000^0 5716' 
Stone calcareous tender to 516-^- 






to 5652 

to 5686 

to 5130 

to 5003 

to 4068— 436S 




-4 or 

GOLD, wiih 



Mir'le white 

Marble common 

Stone calcareous hard 





Stone calcareous soft 

Clay - 







10000 to 2474-9304 

to 8956 


to 7342 

■ to 7383 



lo 7368—7627 

to 7103—5232 

to 6526—7500 

t. 6324-6051 

. to 6087—5811 

to 5S It— 5077 

to 5658—7043 

to 5526 - 5593 

to 5395—6348 

to 5349- 4462 

to 4571—4452 

to 2989—3293 

YOL. X. 




ZINC, with 


Marble white 

Gres - 



Stone calcareous soft 






First Entire 
Refrig^. Refrig. 

lOOOO to 8904—8990 
to 8S05— 8424 

to 6242—7333 

to 6051—7947 

to 6777—6240 

to 5536—7719 

to 5484—7458 

to 5343—7547 

to 5246—6608 

to 3729—5862 

to 3409—4261 


SILVER, with 

Marble white 
Marble common 
Stone calcareous hard 

10000 to 8681—9200 

to 7912—9040 

to 7436—8580 

to 7361—7767 



First Entire 
Refrig. Refrig. 

Glass - - 10000 to 7930— 7212 

Lead - - to 7154— 9184 

Tin - - to 6176—6289 

Stone calcareous soft to 6 1 78 — 6289 

Clay - - to 6034— 6710 

Bismuth - to 6308—8877 

Porcelain - - to 5536— 5242 

Antimony - to 5692—7653 

Oker - to 5000—5668 

Chalk - - to 4310— 5000 

Gypsum - to 2879—3366 

Wood - to 2253—1864 

Pumice-stone to 2059 — 1525 


Marble common 10000 to 8992—9405 

Stone hard - to 8594—9130 

Gres - to 8286—8990 

Lead - - to 7604— 5555 

Tin - - to 7143— 6792 

Stone calcareous soft to 6792—7281 

Clay . - to 6400— 6286 

Antimony - to 6286—6792 

Oker - - to 5400—5571 

Gypsum * - to 4920— 5116 

Wood - to 2200—2857 


140 bupfon's 


First Entire 
Refrig. Refrig, 

Stone hard - 10000 to 9483—9665 

Gres - - to 8767— 9273 

Lead - (o 7671—8590 

Tin - - to 7424— 6666 

Si one soft - - to 7327— 7 &59 

Clay - to 7272— 7213 

Antniiony - to 6279—8333 

Oker - to 6136-6393 

Chnlk. - - to 5581— 6333 

Wood - - . to 2500— 327^ 


Gres - - 10000 to 9268— 9355 

Glass . - to 8710—8352 

Lead - - ■ to 8571— 7^31: 

Tin - - 1 1095—7931 

S?one soft - to 80 -0—8. 95 

Clay - - to 6190—6897 

Oker - - to4762— 55i7 

Wood - . 10 2195—4516 

GRES, with 

GIrss - - lO'^OO to 9324— 79^9 

Lead - to 856 1 —8950 

Tin - - to 7667— 7633 

Stone soft - to 7644—7 !93 

Porcelain - to 7c>64 — 7059 







First Entire 
Refrig. Reirig. 

10000 fo 73 >s— 6 ro 

to 4368—5000 

to 2368—4828 

GLASS, ^Tith 









10000 tof^SIS— 8548 

to9 07— 86"9 

to 7938—7643 

to 7^.fJ2— 8863 

- — to 628^>— 6500 

to 6104—6195 

to 4160—6011 

to 2647—5514 


Stone soft 







LEAD, with 


10000 to 8695 

to 8437—7192 

-— to 7878—8536 

to 8698—8750 

to 8241—8201 

to 6060—7073 

to 5714—6111 

to 4736—5714 


TIN, with 

10000 to 8823—9524 

. to 8889—9400 

to 8710—9156 

to 5882—7619 





First Entire 
Refrig. Refrig. 

10000 to 6394 6842 
to 4090 4912 





10000 to 7742—9342 

r to 7288—7312 

to 4182—5211 

CLAY, with 






10000 (o 8870— 94J6 

— _ to 8400—8571 

to 7701 8000 

to 5186- 8055 

to 3437 4545 

BISMUTH, ^ilh 

A ntimony 



10004 to 9349—9572 
to 8846 7380 
to 8020—9500 



lOOOO to 5301 6500 



10000 to 8431—7391 
to 3833 5476 

OKER, with 




10000 to 8954—8889 

— _ to 6364—9062 

■- — to 4074—5128 



First Entire 
Refrig. Refri^. 

CHALK, with 

Gypsum - - lOOOO to 6667— 7920 

GYPSUM, with 

Wood - - 10000 to 8000 ---5260 
Pumice-stone - to 7009—4560 

WOOD, with 
Pumice-stone - 10000 to 8730—8182 

Notwithstanding the assiduity I used in my 
experiments, aiid the care I took (o render the 
relations exact, I own there are still some im- 
perfections in the foregoing table ; but the de- 
fects are trivial, and do not much influence the 
general results ; for example, it will easily be 
perceived, that (he relation of zinc to lead 
being 10,0000 to 6,0,51, that of zinc to tin 
should be less than 6,000, whereas it is found 
6,777 in the table. It is tlie same with respect 
of silver to bismuth, which ought to be less 
than 6,308, and also with regard of lead to 
clay, which ought to be more than 8,000, but 
in the table is only 7,878. This difference 
proceeded from the leaden and bismuth bullets 
not being always the same ; they melted, as 
well as those of tin and antimony, and, there- 
fore, could not fail to produce variations, the 


144; buffon's 

greatest of wbicli are the three I have just re- 
marked. It was not possible for me to do 
better; the different bullets of lead, tin, bis- 
muth, and aniimony, ^vJiich I successively 
made use of, were made in the same manner, 
bul the matter of each might be somewliat dif- 
ferci'.t, according; to the quantity of the alloy in 
the lead and tin, for I liad pure tin only tor 
the two first bullets; besides, there remains 
very often a small cavity in the melted bullet, 
and these little causes are sufficient to produce 
the litlle differences which may be remarked 
in the table. 

On the whole, to draw from these experi- 
ments all the profit that can be expected, the 
matters which compose their object mustbcdi- 
vided into four classes, viz. 1. Metals. 2 Se- 
mi-metals and Metallic Minerals. 3. Vitreous 
and Vitrescible Substances. And 4. Calca- 
reous andCalcinable substances. Afterwards 
the matters of each class mu t be compared 
between themselves to discover the cause, or 
causes, or the order w hic!i folio .vs the progress 
of heat in each, and ihen with each other, in 
order to deduce some general results. 

First. The order of ihc six metals, accord- 
ing to their densiU/, is tin, iron, copper, silver, 
lead, and gold; v.hereas the order in which 



tliey receive and lose their heat is tin, lead, sil- 
ver, gold, copper, and iron ; so that in tin 
alone it retains its place. 

The progress and duration of heat in metals 
<ioes not then follow the order of their density, 
except in tin, which being the least dense, is 
also that which soonest loses its heat ; but the 
order of the five other metals demonstrates that 
it is in relation to their fusibility that they all 
receive and loose heat ; for iron is more diffi- 
cult to melt than copper, copper more than 
gold, gold more than silver, silver more than 
lead, lead more than tin ; and therefore we 
may conclude that it is only by chance if the 
density and fusibility of tin be found so unitea 
as to place it in the last rank. Nevertheless, 
it would be advancing too much to pretend 
that we must attribute all to fusibility, and no- 
thing to density. Nature never deprives her- 
self of one of her properties in favour of ano- 
ther in an absolute manner ; that is to say, in 
a mode that the first has not any influence on 
the second. Thus,' density may be of some 
weight in the progress of heat ; but we may 
safely aflirm, that in the six metals it has very 
little comparatively with fusibility. 

This fact was neither known to chemists nor 
naturalists ; they did not even imagine that 
gold which is more than twice as dense as iron, 
VOL. X. U nevertheless 

146 . BUrF0N*9 

nevertheless loses its heat near a thiird soonefi 
It is the same with lead,. silver, and copper, 
■which are all more depse than iron, and Avhich, 
like gold, hept and cool more readily ; for 
thou;^li the object of this second memoir -vvas 
only refrigeration, yet the experiments of the 
one that preceded it demonstrate, that there is 
ingress and egress of heat in bodies, and that 
those which receive it most quickly also lose 
it- the soonest. 

. . if we reflect on the real principles of density, 
and the cause of fusibility, we shall perceive, 
tliatdensity depends absolutely on the quantity 
of matter which Nature places in a given space.; 
that the more she can make it enter therein, the 
more density there will be, and that gold, in this 
respect, is of all substances, that which con- 
tains the most matter relatively to its volume. 
It is for this reason that it has been hitherto 
thought, that more time is required to heat or 
cool gold than other metals ; and it is natu- 
ral enough to suppose, that containing double 
ortreble the matterinthe same volume, double 
or treble time would be required to penetrate 
it with heat ; nay this would be true, if in 
every substance the constituent parts were of 
the same figure and ranged the same. But in 
the most dense the molecules of matter arc, 
probably, of a figure sufficiently regular not to 
leave very void places between them 3 in others 



wbichare not so dense, andtbeir iignres more 
irregular, more vacuities are left, and in tlie 
lifijhest, llie molecules being few, and most 
likely of a very irregular figure, a tbousand 
times more void is found than plenitude ; for it 
may be demonstrated by other experiments, 
tbat the volume of even the most dense sub- 
stance contains more void space thanfull matter. 

Now, the principal cause of fusibility is the 
facility which the particles of Jieat find in se- 
parating these molecules of full matter from 
each other ; let the sum of the vacuities be 
greater or less, which causes density or light- 
ness, it is indifferent to the separation of the 
molecules which constitute the plenitude; 
and tlie greater or less fusibility depends en- 
tirely on the power of coherence which retains 
the massive parts united, and opposes itself 
more or less to their separation. The dilata- 
tion of the total volume is the first degree of 
the action of heat ; and in different metals it is 
made in the same order as the fusion of the 
mass, which is performed by a greater degree 
of heat or fire. Tin, which melts the most rea- 
dily, is also that which dilates the quickest ; 
and iron, which is the most difBcultof all to 
melt, is likewise that whose dilatation is the 

After these general positions, which appear 
clear, precise, and founded on experiments 


143 buifok's 

tliat nothing can contradict, it might be iiiia'sr 
gincd that ductility would follow the order of 
fusibility, because the greater or less ductility 
seems to depend on (he greater or less adhesion 
of ihe parts in each metal ; neyerlheh ss, ducti- 
lity seems iohaveasmuch connection with the 
order of density, as with that of their fusibility. 
I would even afhrra that it is in a ratio com- 
posed of the two others, but that would be only 
by estimation, and a presumption which is,'per- 
haps not founded ; for it is not so easy to ex- 
actly determine the different degrees of fusibi- 
lity, as those of density ; and as ductility parti- 
cipates of both, and varies accordir)g to cir- 
cumstances, we have not as yet acquired the 
necessary knowledge topronounceaffirmativcr 
ly o this subject, though it is most certainly 
of sufficient importance to merit particular 
researches. The same metal when cold gives 
very different results to what it does when 
Lot, although treated in the same man- 
ner. Malleability is the first mark of duc- 
tility ; but that gives only an iraj^crfect idea 
of the point to which ductility may extend ; 
nor can simple lead, the most malleable 
metal, be diawn into such fine threads as 
gold, or even as iron, which is the least mal- 
leable. Besides we must assist the ducti- 
lity of metals with the addition of fire, with- 


out \vhich the J become brittle : even iron, al-r 
thoug-h the raost robust, is brittle like the rest. 
Thus the ductility of one metal, and the ex- 
tent of continuity ^vhich it can support, dc^ 
pcnd not only on its density and fusibility, 
but also on the manner and space in which it 
is treated, and of the addition of heat or fire 
T^hich is properly given to it, 

II. By comparing those substances which 
we term semi-metals and metallic jninerals^ 
which want ductility, we shall perceive, that 
the order of their density is emery, zinc, an- 
timony and bismuth, and that in which they 
receive and lose heat, is antimony, bismuth, 
zinc, and emery ; and which does not in any 
measure follow the order of their density, but 
rather that of their fusibility. Emery, which 
is a ferruginous mineral, although as dense 
again as bismuth, retains heat longer. Zinc 
which is lighter than antimony or bismuth, 
retains heat longer than either. Antimony 
and bismuth, receive and keep it nearly alike. 
There are, therefore, semi-metals, and metallic 
minerals, whicli, like metals, receive and lose 
heat nearly in the same relation as their fusi- 
bility, and partake very little of their density. 

But by joining the six metals, and the fotir 
^f^mi- metals, or nietallic minerals, which I have 



ii'lcdy we siiall find the order of the densities of 
lliese ten mineral substances to be emery, zinc, 
antimony, tiii, iron, copper, bismuth, silver,' 
lead and gold. And that tlie order in which 
these subsl*inces heat and cool, is antimony, 
bismulh, tin, lead, silver, zinc, gold, copper, 
emery and iron, in which there aretwothings 
that do not appear to perfectly agree with the 
order of fiidbilily. 

First, Antimony, which, according to New- 
ton, should heat and cool slower than lead, 
since by his experiments it requires ten degrees 
of the same heat to fuse, of which eight are suf-. 
ficicnt for lead ; whereas by my experiments 
antimony is found to heat and cool quicker; 
than lead. But it should be observed that 
]J»'ew(on made use of the regulus of antimony, 
and that I employed only melted antimony in 
experiments. Now this regulus of antimony, 
or native antimony, is much more difficult to 
fuse than antmiony which has already under- 
ffone a first fusion, therefore that does not make 
an exception to the rule. On the whole, I do 
not know Avhut relation native antimony, or 
Fegulus of antimony, may have with the other 
matters I have heated and cooled ; but I pre-. 
sume, from the experiments of Newton, that 
it heats and cools slower than lead. 



Secondly, it is pretended, that zinc fuses 
more easily than silver, consequently it should 
be found before silver in the ordei indicated 
by experiments, if this order were in all cases 
relative to that of fusibility ; and I own that this 
semi-metal seems, at the first glance, to make 
an exception to the law which is followed by 
all the others ; but it must be observed, tliat the 
ditference given by my experiments betweea 
zinc and silver is very trifling. The small 
globe of silver which I made use of was of th^ 
purest silver, without the least mixture of cop- 
per ; but I had my doubts whether that of zinc 
were entirely free from copper, or some other 
metal less fusible; and therefore, after all my 
experiments, I returned the globe of zinc to 
M. Rouelle, a celebrated professor of chc-^ 
mistry, requesting him carefully to examine 
it, which having done, afier several trials, he 
found a pretty considerable quantity of iron, 
or saffron of sleel in it. 

I have, therefore, had the satisfaction of 
seeing that not only my own supposition was 
well founded, but also that my experiments 
have been made with sufhcient precision to 
evince a mixture. Thus zinc exactly follows 
the order of fusibility, like the other metals and 
semi-metals, in the progress of heat, and does 
not piake any exception to the rule, li caa» 



not (Iierefbre, in general, be said tliat the proi 
gross of heat in metals, semi-metals, and me- 
tallic minerals, is in the same ratio, or even 
nearly to that of their fasibility. 

III. The Vitrescible and Vitreous Matters, 
which I tried, beiivg ranged according to their 
density, are, pumice-stone, porcelaine, oker, 
clay, glass, rock-chrystal, and gres, for I 
must observe, that although chrystal is not 
set down in the table of the weight of each 
matter but for six drachms 22 grains, it must 
be supposed one drachm heavier, because it 
was sensibly too small; and it was for this 
reason that I excluded it from the general table 
of relations; nevertheless, as the general result 
agrees with the rest, I can present the follow- 
ing as the order in which these different sub- 
stances are cooled : 

Pumice-stone, oker, porcelain, clay, glass, 
crystal and gres, is according to that of theit 
density, for the oker is here before the porcelain 
only because, being a fusible matter, it dimi- 
nished by the friction it underwent in the ex- 
periments, and, besides, their density differs so 
little that they may be looked upon as equal. 

Thus the law of the progress of heat in 
vitrescible and vitreous matters is relative to 
the order of their density, and has little or no re- 
lation with their fusibility but by the heat re- 


quired to fuse th^se substances being in an 
almost equal degree, and the particular degree 
. of their different fusibility being so near each 
other that an order of distinct terms cannot }3e 
made ; thus their almost equal fusibility mak- 
ing only one terra, which is the extreme of this 
order, we must not be astonished that the pro- 
gress of heat here follows the order ofdensity, 
, and that these different substances, which are 
.all equally difjScult to fuse, heat and copl 
more or less quick in proportion to. the matter 
they contain. 

It may be objected to rae that glass fuses 
more easily than , clay, porcelain, oker, aod 

pumice-stone, which, nevertheless, heat and 
cool in less tinie than glass ; but the objection 

will fail when we reflect, that to fuse glass it is 
requisite to have a very fierce fire, the heat of 
which is so remote from the degrees which 
glass receives in our experiments on r<?frigera- 
tion, that it cannot have any influenot on them. 
Besides, by powdering clay, porcelain, and 
pumice-stone, and by giving them their analo- 
gous fusers, as we give to sand to convert it 
into glass, it is more than probable that we 
should fuse all the matters in the same degree 
of fire, and that, consequently we must look 
upon it as equal; or almost equal, with their 
TOL. X. X resistanet 

IM BUFFO n'^^ 

tesistance to fusion ; and it is for this reasott 
that the law of the pron^ress of heat in these 
matters is found proportionable to the order 
of their density. 

ly. Calcareous matters, ranged according* 
to the order of their density, are, chalk, scft 
stone, hard stone, common marble, and white 
marble, which is the same as that of their den- 
sity. The fusibility is not here of any weight, 
because it requires at first a very great degree 
of fire to calcine them; and although the cal- 
cination divides the parts, we must look upon 
the effect only as a first degree and not as a 
complete fusion. The whole power of the 
best burning mirrors is scarcely sufficient to 
perform it. I have melted and reduced into 
a kind of glass some of these calcareous mat- 
ters; and i am convinced that these matters 
may, like all the rest, be reduced ulteriorly 
into glass, without employing for this purpose 
any fusfng matter, and only by the force of a 
fire superior to that of our furnaces ; conse- 
quently the common term of their fusibility is 
still more remote, and more extreme, than that 
of vitreous matlers, and it is for this reason 
that they also follow more exactly the order of 
density in the progress of heat. 
White gypsum, improperly called alabaster, 



is a mat/er which calcines like all other plasters 
fej a more modera<e heat than that which is 
necessary for the calcination of calcareous 
matters, and it follows tlie order of density in 
the progress of heat which it receives or loses, 
for although much more dense than chalk, and 
a little more so than v/hite calcareous stone, it 
Jieats and cools more readily than either of 
those matters. This demonstrates that the 
more or less easy calcination and fusion pro- 
duces the same effects relatively to the pro- 
gress of heat. Gypsous matters do not require 
so much fire to calcine as calcareous^ and it is 
for this reason that, although more dense, 
they heat and cool much quicker. 

Thus it may be concluded, that, in general, 
the progress of heat in all Mineral Substances 
is alwaj/s nearly in a ratio of their greater or 
less facility to calcine, or melt : but that when 
their calcination, or their fusion, are equallj/ 
dijficidt'i and that thei/ require a degree ofeX" 
treme heaty then the progress of heat is made 
according to the order of their densiii/, 

I have deposited in the Royal Cabinet the 
globes of gold, silver, and of all the other 
metallic and mineral substances Tvhich served 
far the preceding experiments, that if the truth 
pf their results^ and the general consequences 


156 buffon's 

whicli 1 have deduced, be doubtiedy there may 
be an opportunity of rendering them more 


WE have already seen, that of all the Mi- 
neral substances which I subjected to trial it 
was not the most dense, but the least fusible, 
which required the longest time to receive and 
lose heat. Iron and emery, ^vhich are the 
most difficult matters to fuse, are, at the 
same time, those that heat and cool the 
slowest. There is nothing except platina 
that is accessible to heat, which retains it 
longer than iron. This mineral, (which has 
not long been publicly mentioned) appears, 
however, to be more difficult to fuse ; the fire 
of the best furnaces is not fierce enough to prc- 
duce that effect, nor even to agglutinate the 
small grains, which are all angular, hard, 
and similar in form to the thick scale of iron, 
but of a 3^ellowish colour ; and although we can 
fuse them without any addition, and reduce 
them into a mass by a mirror, platina seems to 
require more heal than the ore and scales of iron 



wtich we easily fuse in our forge furnaces. 
In other respects, the density of piatina being 
much greater than that of iron, the two quan- 
tities of density and non-fusibility unite here to 
retider this matter the least accessible to the 
progress of beat. I presume, therefore, that 
piatina would have been at the head of my table 
if I had put it to (he experiment; but I was 
not able to procure a globe of it of an dia- 
meter, it being only found in grains* ; and that 
which is in the mass is not pure, it being ne- 
cessary, in order to fuse it, to mix it with other 
matters, which alter its nature. The Comte 
de Billarderie d'Angivilliers, who often at- 
tended my experiments, led me to examine 
this rare metallic substance, not yet suQiciently 
known. Chemists who have employed their 
time in plutir.a, have looked upon it as a new, 
|>erfect, proper, and particular metal, different 
from all the rest ; they have asserted, tliat i(s 
specific weight was nearly equ^l to that of gold; • 
Ijut that it essentially differed in other respects 
from gold, having neither ductility nor fusibi- 
lity. I own I am of a quite contrary opinion ; 
because a matter which has neither ductility 
nor fusibility, cannot rank in the number of 


* I have been assured, however, by a person of the first 
respectability, that piatina is sometimes found in masses, 
and that he himself saw a piece that weighed twenty 
pounds, pure as it was extracted from the mine. 

loS BUFFO n's 

Kielals, whose essential and common pro» 
periies are to be ductile and fusible. JNeithcr, 
aitcr a very careful examiuationj did pl.iiina 
appear (o nie a new metal different from every 
olker, but rather an alloj of iron and gold 
formed by Nature, in which the quantity of 
gold predominated over the iron ; ai.d J found* 
ed this Oj7inion on tlie following facts : 

Of S ounces 85 grains of plutina, furnished 
mc by Comied'AngiviilitTs, yvhich 1 presented 
to a fetrong loadbtane, there remained only 1 
©ujice, i dram, awd 98 grains, all ihe rest was 
taken avvay by the loadstone ; tii ere fore, nearly 
six-scvcmiis ot the whole was attracted by thq 
loadstene, \Yliich is so considerable a quantity, 
that it is iiriposbibte to suppose that iron is not 
contained intheintimaie substance of platiiia, 
b«t that it is even there in a very great quan- 
tity. I am convinced it contains much more, 
for ii 1 had not been weary of these experi- 
naents, which took me up several days, I should 
have attracted a great part of the remainder 
of the 8 ounces by my loadstone, for to the 
last it continued to draw some grains one by 
one, and sometimes two. l here is, therefore, 
iMuch iron in platina, and it is not simply 
jMixed with il, as with a foreign matter, but in- 
limately united and making part of it» bubf 

stance i 


stance; or, if this is denied, it must be sup- 
posed, that there exists a second matter m 
Nature which like iron may be attracted by 
the loadstone. 

All the platina I have had an opportunity of 
examining, has appeared to be mixed with two 
different matters, the one black, and very at- 
tractable by the loadstone ; iha other in larger 
grains, of a pale yellow, and much less mag- 
netic than the first. Between tliese two mat- 
ters, which are the two extremes, are found all 
the intermediate links, whether with respect- 
to magnetism, colour, or size of the grains. 
The most magnetic, which are at tlie same 
time the blackest and smallest, reduce easily 
into jwwder by a very slight friction, and leaye 
on white papier the same marks as lead. Seven 
leaves of paper which were .successively made 
use of to expose the platina to the action of 
the loadstone, were blackened over the whole 
extent occupied by it ; the la»t left less tlian the 
first, in proportion as the grains which remain- 
ed were less black and magnetic ; the largest 
grains, which are yellow, and least magnetic, 
instead of crumbling into powder like the 
small black grains, are very hard, and resist all 
' trituration ; nevertheless, tlicy are SLi>ceplit)ie 
of extension in an agate mort;tr, under tlie 
reiterated strokes of a pestle of the same mat- 

]60 buffon's 

ter, and I flaUened and extended many grains 
to the double or treble cxtoiit of tbcir surface : 
this part of platina, therefore, has a certain 
degree of malleabiiitj', and duclility, whereas 
the black part appears to be neither malleable 
nor ductile. The intermediate grains parti- 
cipate of the qualities of the two extremes : 
they are brittle and hard, tliey break or ex- 
tend under the strokes of the pestle, and afford 
a little powder not so black as the £rst. 

Having collected this black powder and the 
most magnetic grains that the loadstone at 
first attracted, I discovered that the whole 
A^as iron, but in a different state from common 
iron. The latter reduced into powder and 
filings contracts moisture, and rusts very 
readily ; in proportion as the rust increases, it 
becomes less magnciic, and absolutely loses 
this magnetical quality when entirely and in- 
timately rusted; whereas this iron powder, or 
ferruginous sand found in Iheplatina, is inac- 
cesssible to rust, how long soever it may be 
exposed to the air and humidity; it is also 
more infusible and much less dissoluble than 
common iron; but is, nevertheless, an iron 
V, liich appears to differ only from common iron 
by a greater purity. This sand is, in fact, iron 
divested of all llie combustible matter and all 
terrene paits wliich are found in common iron, 



and rven in stx^el. It appears endowed and co- 
vered with a Wtreous varnish which defends 
it from all injury. What is very rcnarkable, 
this pure iroR sand does not exclusively belong 
to the platinaore; for I have found it, although 
always in small quantities, in many par(s where 
theiron ore has been dug, and which consumed 
in my forges. As I submilted to several trials 
all the ores I had, before I used ihem in rny 
t;xpcrimen(s, I was surprised to find in some 
of them, which were in grains, parlicles of 
iron, somewhat rounded and shining, like the 
tilings of iron, and perfectly resembling the 
ferruginous sand of the platina ; they were all 
as magnetic, all as little fusible, and all as dif- 
ficult of solution. Such was the result of the 
comparison I made on the sand of platina, 
and of the sand found in both my iron ores, at 
the depth of three feei, in earths where wa- 
ter easily ]3enctrated. 1 was puzzled to conceive 
whejice these particles of iron could proceed, 
how they had been defended against rust for 
the ages they were exposed to the humidify 
of the earth, and how this very magnetical 
iron had been produced in veins of mines, 
which had not the smallest degree of that qua- 
lify. I called experience to my aid, and became 
at lengfh satisfed upon these points. I was 
TOI-- X. Y well 

1C2 buffon's 

well convinced that none of our iron ores in 
grain were tractable by the loadstone, and 
well persuaded that all iron ores, which are 
magnetical, have acquired that property only 
by the action of fire : that the mines of the 
north, which are so raagnelical as lobe sought 
after by the compass, must owe their origin to 
.fire, and are formed by the means, or the inter- 
medium of water; from which I was induced 
to suppose that this ferruginous and magnetic 
sand, that I found in a small quantity in my 
iron mines, must owe its origin to fire, and 
having examined the place I was confirmed in 
this idea. This magneticul sand is found in a 
wood, where, from time immemorial, they 
have made, and still continue to make, coal 
furnaces. It is likewise more than probable that 
there were formerly considerable fires here. 
Coal and burnt wood produce iron dross, 
whicli includes the most fixed parts of iron 
that vegetables contain ; it is this fixed iron 
which forms tlie sand here spoken of, when thtf 
dross is decomposed by the action of the air, 
sun, and rain, for then these pure iron parti- 
cles, which arc not subject to rust, nor to any 
otlier kind of alteration, suffer themselves to be 
carried away by tlie water, and penetrate with 
it some feet deep into the earth. What I here 



advance may be verified by grinding the dross 
well burnt, and there will be found a small 
quantify of this pure iron, which, having re- 
sisted the action of tlie fire, equally resists that 
of the solvents, and does not rust at all. 

Being satisfied on this head, and having 
sufficiently compared the sand and dross ta- 
ken from th« iron ores with that of the platina, 
so as to have no doubt of their identity, it was 
not long before I was led to conclude, consi- 
dering the specific gravity of platina, that if 
this pure iron sand, (proceeding from the de- 
composition of dross) instead of being in an 
iron mine, was found near to a gold one, it 
might, by uniting with tliat metal, form an al- 
loy which would be absolutely of the same na- 
ture as platina. Gold and iron have a great 
affinity ; and it is well-known that most iron 
mines contain a small quantity of gold ; it is 
also known how to give to gold the tint, co- 
lour, and even the brittleness of iron, by fusing 
them together. This iron-coloured gold is 
used on difl:erent golden jewels to vary the co- 
lours ; and this gold mixed witli iron is more 
or less grey, and more or less tempered, accord- 
ing to the quantity of iron which enters the 
mixture. I have seen it of a tint absolutely 
like the colour of platina ; and having enquir- 

164 buffon's 

cd of a goldsmith the proportion of gold anej 
iron (herein, he informed rac, (hat in a piece 
of 'i4 carats, there were no more than 18 gold, 
consequently a fourth p irt was iron, which is 
nearly the propartion found in (he natural pla- 
tina, if we judge of it by the specific weight; 
and this gold made with iron is harder and 
specifically less weighty than pure gold. All 
these agreements and common qualities with 
platina, have persuaded me, that this pretend- 
ed metal is, in fact, only an alloy of gold and 
iron, a!)d not a particular substance, a new 
and perfect metal different from every other, 
as cbeinis(s have supposed. 

It is well known \hal alloy makes all me(ais 
brittle, and that when there is a penetration, 
that is, an augmentation in the specific gravity j 
the alloy is so much the more tempered as the 
penetration is the greater, and the mixture be- 
comes the more intimate, as is {perceived in the 
alloy crdled bell-metal, although it be com- 
posed of two very ductile metals. Now no- 
thing is more tempered, nor heavier than pla- 
tina, which alone ought io make us conclude 
that it is only an alloy made by Nature, a 
mixture of iron and gold, owing in part its 
fpecific gravity to this last, and, perliaps, al- 
so, in a great part, to the i>enet ration of the 
two matters of which it is composed. 



As this matter, heated alone and without 
any addition, is very difScult to reduce into a 
mass, as by the fire of a burning mirror we caa 
obtain only very snaall masses, and as fhe hy- 
drostaticnl experiments made on small vo- 
lumes are so defective, that we can not conclude 
any thing therefrom, it appears to me that the 
chemists bave been deceived in their estima- 
tion of the specific gravity of this mineral. I 
put some powder of gold in alitde quill, whicli 
I weighed very exactly ; I put in the same 
quill an equal yolume of platina, and it weigh- 
ed nearly . a tenth less ; but this gold powder 
was much too fine in comparison of the pla- 
tina. M. Tiiiet, who besides a profound know- 
ledge of metals, possessed the talent of mak- 
ing experiments with the greatest precision, 
repeated, at my request, this experiment up- 
on the s|)ecific weight of the platina, com pared 
to pure gold; for tliis purpose, he, like me, 
made use of a quill, and cut gold of 24 c:irats, 
reduced as much as possible to the size of the 
grains of platina, and he found, by eight ex- 
periments, that the weight of platina differed 
from that of pure gold very near a fifteenth? 
but we both observed that the grains of gold 
had much sh a per angles than the platina: all 
the angles of the latter were blunt, and even 
soft, whereas the grains of this gold had sharp 


I^ buffon's 

and culting angles, so that they could not 
adjust themselves, nor heap one on the other 
as easily as those of platina. The gold pow- 
der I had before made use of Tyas such as is 
found in river sand, whose grains adjust them- 
selves much better one anjainst the otlier, and 
I found a about a tenth difference between the 
specific weight of thoic and platina ; neverthe- 
less, those are not pure gold, more than tw^o or 
three carats beinsc often wantinrr, which must 
diminish the specific weight in the same rela- 
tion. Thus we have thongl^t we might main- 
tain, from the result of my experiments, that 
platina in grains;, and such as Nature produces 
if, is, at least, an eleventh, or twelfth, lighter 
than gold. There is every reason to presume 
that the error on tlie density of platina, pro- 
ceeded from is not having been weighed in its 
natural state, but only after it had been re- 
duced into a mass ; and as this fusion cannot 
be made but by the addition of other matters, 
and a very fierce fire, it is no longer pure pla- 
tina, but a composition in which fusing mat- 
ters are entered, and from which fire has taken 
the lightest parts. 

Platina, therefore,insteadofbeing of a density 
almost equal to that of pure gold, as has been 
asserted, is onlj^ density between that of gold 



and iron, anclonly !>earer this :first metal than 
the last. For supposing that the cube foot of 
gold weighed 13:-61b and that of iron 280, that 
of platina in grains will be found to weigh 
about 11911b. which supposes more than | of 
gold to 5 of iron in this alloy, if there is no 
penetration ; but as we extract | by the load- 
stone, it might be thought, that there is more 
than I iron therein : especially as by conti- 
nuing this experiment, I am persuaded, we 
should be able, wit h a strong loadstone to bring 
away all the platina even to the last grain. 
Nevcrtlieless, we must not conclude that iron 
is contained therein in sogreat a quantity; for 
when it is mixed by the fusion with gold, the 
mass Xvhich results from this alloy is attractable 
by the loadstone, although the iron is in no 
great quantify therein. M. Baume had a piece 
of this alloy weigliingGG grains, in which was 
only entered 6 grains, that is, ^\- of iron, and 
this button was easily taken up by the load-- 
stone. Hence the platina might possibly con- 
tain only yV i**on, or fi gold, and yet be at- 
tracted entirely by the loadstone; and this per- 
fectly agrees with the specific weight which is 
^V less than gold. 

.But what makv?s me presume, that plitina 
contains more than -^j of iron, or ff of gold, 


t6S ijgpfon's 

is, that the alloy from fhis proportion is slill 
t)f the gold colour, and much yellower Ihaft 
the highest coloured platina, and that | iron, 
or I gold is requisite for the alloy to be pre* 
ciscly of the natural colour of platma. lam, 
therefore, greatly inclined to think that there 
might possibly be this quantity of | iron in 
platina. We were assured by many experi- 
wicnts, that Uic sand of this pure iron which 
contained platina, is heavier than the filings 
of common iron. Tlius, this cause, added to 
the efil'ct of penetration, is suflficient for th^ 
reason of this gre^it quantify of iron contained 
under the small volume indicated by the spe- 
cific weight of platina. 

On tlie whole, it is very possible that I may 
be deceived in some of the consequences which 
I have drawn from my observations on this 
metallic substance : for I ha\'e not been able 
to make so profound an examination as I 
cotildwish; and wha.t I say is only what I 
Iiave observed, which may perhaps serve as 
a stimulus to other and better researches. 

Chance led me to tell my ideas to Contc de 
Milly, who declared himself nearly of my opi- 
nion. I gave him the preceding remarks to 
inspect, and two days after he favoured me 

wit U 


with the following observations, and which he 
iias permitted me to publish. 

" I weighed exactly thirty-six grains of 
platina ; I laid them on a sheet of white paper 
that I might observe them the better with a 
-magnifying glass : I perceived three different 
substances; the first had the metallic lustre, 
and was the most abundant ; the second, draw- 
ing a LuIq on the black, very nearly resembled 
a ferruginous metallic matter, which could 
undergo a considerable degree of fire, such 
as the scoria of iron, vulgarly called mackefer: 
the third less abundant than the two first, i. e. 
sand, where the yellow, or topaz colour, is 
ih.6 most predominant. Each grain of sand, 
considered separate, offered (o the sight regu- 
lar chrystals of different colours. I remarked 
some in an hexagon form, terminating in 
pyramids like rock chrystal ; and this sand 
seems to be no otlier than a detritus of chrys- 
tal, or quartz of different colours* 

'' I resolved On separating, as exactly as 
possible,these different sub^ances, by means of 
the loadstone, and to put aside the parts most 
attractable by the Loadstone, from those which 
were less, and both from those which were not 
so at all ; then to examine each substance par« 
ticularly, and to submit them to different che- 
mical and mechanical heats, 
^'OL. X. Z ^'l sepa- 

170 buffom's 

'^ I separated these par(s of the platina 
which were briskly attracted at the distance of 
two or three lines ; that is to say, without the 
contact of the loadstone ; and for this experi- 
ment I made use of a good fictious magnet; I 
afterwards touched the metal with this mag* 
net, and carried ofFall that would yield to the 
magnctical ft.rce. Being scarcely any longer 
attractable, I weighed what remained, and 
whicli I shall call No. 4 ; it was twenty-four 
grains; No. 1, which was the most sensible to 
the magnet, weighed four grains; No. 2 
weighed the same ; and No. 3, five grains 

" No. i , examined by the magnifying glass^ 
presented only a mixture of metallic parts, a 
white sand bordering on the greyish, flat and 
round, or black vitriform sand, resembling 
pounded scoria, in which very rusty parts are 
perceptible : in short, such as the scoria of 
iron presents after having been exposed to 

'' No. 2 presented nearly the same, except- 
ing that the metallic parts predominated, and 
that there were very few rusty particles. 

" No. 3 was the same, but the metallic parts 
were more voluminous ; they resembled melted 
metal which had been thrown into water to be 
granulated ; they were flat, and of all sorts of 
figures, rounded on the corners. 

No. 4, 


*^ No. 4, which had not been carrieJ off by 
the magnet (but some parts of which still af- 
forded marks of sensibility to magnetism , when 
the magnet was moved under the paper where 
they were in), was a mixture of sand, metallic 
parts, and real scoria, friable between the fin- 
gers, and which blackened in the same manner 
as common scoria. The sand seemed to be 
composed of small rock, (opaz, and cornelian 
chryslals. I broke some on a steel, and the 
powder was like varnish, reduced into powder ; 
I did the same to the scoria ; it broke with the 
greatest facility, and presented a black powder 
which blackened the paper like the common, 

*' The metallic parts of this last (So. 4) ap- 
peared more ductile under the hammer than 
those of No. 1, which made me imagine they 
contained less iron than the first : from whence 
it follows, that platina may possibly be no more 
than a mixture of iron and gold made by Na* 
ture, or perhaps by the hands of men. 

'' I endeavoured to examine, by every pos- 
sible means, the nature of platina: to assure 
myself of the presence of iron of platina by 
chemical means, I took No. 1, which was 
very attractable by the magnet, and No. 4, 
which was not; I sprinkled them with fuming 
spirit of nitre ; I immediately observed it with 
the microscope, but perceived nocfiorvcsccnce? 

I added 

172 buffon's 

I added distilled water thereon, and it still 
made no motion, but the metallic parts ac- 
quired new brilliancy, like silver : I let this 
mixture rest for ^ve or six minutes, and hav- 
ing still added water, I threw some drops of 
alkaline liquor saturated with the colouring 
matter of Prussian blue, and very fine Prus- 
sian blue was afforded me on the first. 

^* No. 4, treated in the same manner, gave 
the same result. There are two things very 
singular to remark in these experiments ; first, 
that it passes current among chemists who 
have treated on the platina, that aquafortis, or 
spirit of nitre, has no action on it. Yet, as I 
have just observed, it dissolves it sufficiently, 
though without effervescence, to afford Prus- 
sian blue, when we add the alkaline liquor 
phlogisticated and saturated with the colour- 
ing matter, which, as is known, participates 
iron into Prussian blue. 

^' Secondly, Platina, which is not sensible. 
to the magnet, does not contain less iron, since 
spirits of nitre dissolves it enough, and without 
effervescence, to make Prussian blue. Whence 
it follows^ that this substance, winch modern 
chemists, perhaps toogreedy of the marvellous, 
and too willing to give something novel, have 
considered as a ninth metal, may possibly be 
only a mixture of gold and iron. 

'' Without 


<< Without doubt there still require many 
experiments to determine bow this mixture has 
taken place, if it be the work of Nature or the 
effects of some volcano, or simply the produce 
of the Spaniards' kbours in the New World to 
acquire gold in the mines of Peru. 

" If we rub platina on white linen it black- 
ens it like common scoria, which made me 
suspect that it was the parts of iron reduced 
into scoria which are found in Uiis platina, and 
give it this colour, and which seem, in this 
slate, only to have undergone the action of a 
violent fire. Besides, having a second time 
examined platina with ray lens, I perceived 
therein different globules of liquid mercury, 
which made me suppose that platina might 
be the produce of the hands of man, in the 
follov/ing manner : — Platina, as I have been 
told, is taken out of the oldest mines in Peru, 
which the Spaniards explored after the con- 
quest of tlie New World. In those dark times 
only two methods were kriown of extracting 
gold from the sands wiiich contained it ; first, 
by an amalgarna with mercury ; secondly, by 
drying it. The golden sand was triturated 
with quicksilver, and when that was judged 
to be loaded with the greatest part of the gold, 
the sand was thrown away, which was named 
crass e, as useless and of i\Q value. 



" The otber method was adopted with as little 
judgment ; <o extract it they began by minera- 
lising auriferous metals by means of sulphur, 
which has no action on gold, the specific weight 
being greater than that of other metals : but to 
facilitate its precipitation iron was added, which 
loaded itself with the superabundant sulphur, 
and this method is still followed. The force 
of fire vitrifies one part of the iron, the other 
combines itself with a small portion of the gold, 
or even silver, which mixes with the scoria, 
from whence it cannot be drawn but by strong 
fusions, and being well instructed in the suit- 
able intermediums which are made use of. Che- 
mistry, which is now arrived to great perfec- 
tion, affords, in fact, means to extract the 
greatest part of this gold and silver : but at the 
lime when the Spaniards explored the mines of 
Peru, they were, doubtless, ignorant of the art 
of mining with the greatest profit ; besides, 
they had such great riches at their disposal that 
they, probably, neglected the means which 
would have cost them trouble, care, and time ; 
there is much reason therefore to conclude that 
they contented themselves with a first fusion, 
and threw away the scoria as useless, as well as 
the sand which had escaped thequicksil ver,and 
perhaps they made a mere heap of these two 
mixtures; which Ihey regarded as of no value, 

'' Thcs# 


** These scoria contained goW. and silver, 
iron under different states, and that in different 
proportions unknown to us, but which, per- 
haps, are those that gave origin to the platina. 
The globules of quicksilver which I observed, 
and those of gold which I distinctly saw, 
with the assistance of a good lens, in the plati- 
na I had in my hands, have given birth to the 
ideas which I have written on the origin of 
this mineral; but I only give them as ha- 
zardous conjectures. To acquire some cer- 
tainty we must know precisely where the pla- 
tina mines arc situated, and examine if they 
have been anciently explored, whether it be 
extracted from a new soil, or if the mines bo 
only rubbish,and to what depth thej are found ; 
and, lastly, if they have any appearance of 
being placed by the hands of man there or not, 
which alone can verify or destroy the conjec- 
tures I have advanced." * 

These observations of Comte de Milly con- 
firm mine in almost every point. Nature is the 
same, and presents herself always the same to 
those who know how to observe her : thus we 


* Baron Siekengen, minister of the elector Palatine, 
told M. de. Milly, that he had then in his possession two 
memoirs whic'i had been given to him by M. Kellner, che- 
mist and metallurgist in the service of the Prince of Birc- 
kenfeld, at Manheim, and which oft'cred to the court of 
Spain to return nearly as much gold as they vyould send 
him platina. 

176 buffon's 

must not be surprized that, without any com- 
munication, we observed the siinie things, and 
deduced the same consequence therefrom ; that 
platina is not anew metal, different from every 
other, but a mixture of iron and gold. To re- 
concile his observations still more with mine, 
and to enlighten, at the same time, the doubts 
which remain on the origin and formation of 
platina, I have thought it necessary to add the 
ibllowing remarks : 

1. The Comte de Milly distinguishes three 
kinds of matters in platina, namely ,two, metal- 
lic, and the third, non-metallic, of a chrystal- 
line form and substance. He observed, as well 
as I, that one of the metallic matters is very 
attractable by the magnet, and ihe other but 
Utile, or not at all. I mentioned these two mat- 
ters as well as he, but I did not speak of the 
third, which is not metallic, because there was 
none, or very little, on the platina on which I 
made my observations. It is possible that 
the platina which the Comte m.adc use of 
was not so pure as mine, which, I observ- 
ed with the greatest care, and in which I saw 
only some small transparent globules, like 
white melted glass, which were united to the 
particles of platina, or ferruginous sand, and 
which were carried any where by the magnet* 



'iii'sTORY. '177 

' ^li^sb'ti-alfsparVnt g^of3iil(^s were very" lew, "and 
in eiglit Ounces'of platinaSvliicIi I h'tirr6\vly 
inspected ivitli a very strong' lens, I ne\er 
ipcrceiycd regular crystals. It rather appeared 
to' me "t L at ' al 1 ili e t rahs p a re n f pa r t ib^ cs were 

' gio%uToii'5, like mel-eVf glass, aiivi all attnctied'to 

' niefallic parts ; nevertheress, as 1 (litt'not in tlio 

least doub't the veracity 'of the Comte de Slitly 's 

obserValibn, who observed crystalline parlicies 

"of 6. f&guiar form, anri in a' groat nnhilDer, in 

'Hisptatinn, I thought 1 ought' liot to'con^ne 
myseffsoldy to the examination of lliat p'latina 
of which r have spoken ; hnd finding some m 
the king*s cabinet, M. Dnubeiiton and T ex- 
amined it togc^tlier : tiiis appeared to be riiucli 
less pure thaii tliat we had 'before made our 
experiments on ; and in it we remarked a 

' great number of small prismatic and transparent 
crystals, some of a ruby 'colour, others ofa 

* topaz, and others perfectly wliite, whicfi con- 
vinced us of the correctness of the Comte 
de Milly in his observations; but this only 
proves that there are some mines of platina 
much more pure than others, and that iii tllose 
which are the most so, none of these foreign 
bodies are found. M. l)aubcnton also re- 
marked some grains flat at bottom andrough at 
tbp, like melted metal cooled on a plain, and I 
VOL. X. A a very 

1T8 buffon's 

very distinctly saw one of these hemispherical 
grains, which might indicate that platina is a 
matter that has been melted by the fire ; but it 
is very singular, that in this matter, if melted 
by fire, small crystals, topaz, and rubies, are 
found ; and I know not whether we ought 
not to suspect fraud ia those who supplied this 
platina, who, to increase the quantity, mixed 
it with these crystalline sands, for I never met 
with these crystals but in one half pound of 
platina given me by the Comte de AngilUviers. 
2. 1, as well as Comte de Milly, found gold 
sand in platina ; it is readily discovered by its 
colour, and because it is not magnet ical ; but 
I own that I never perceived the globules of 
mercury which he states to have done ; yet I 
do not mean therefore to deny their exist- 
ence, only that it appears to me that the sand 
of gold meeting with the globules of mercury, 
in the same matter, they might be soon amal- 
gamated, and not retain the colour of gold, 
which Ihaveremarked in all the gold sand that 
I could find in half a pound of platina ; besides, 
the transparent globules, which I have just 
spoken of, resemble greatly the globules of live 
and shining mercury, insomuch that at the 
tkbt glance it is easy to be deceived in them. 

3. There 


3. There were by no means so may tar- 
nisbed and rusty partsin my first platina asin 
that of Comte de Milly's. nor was it properly 
a rust which covered the surface of those fer- 
ruginous particles, but a black substance pro- 
duced by fire, and perfectly similar to tbat 
which covers the surface of burnt iron. But 
my second platina, that which I had from the 
royal cabinet,had a mixture of some ferruginous 
parts, which under the hammer were reduced 
into a yellow powder,and had all the characters 
of rust. This platina therefore of the royal 
cabinet,andthat of Comte deMilly, resembling 
in every respect, it is probable that thoy pro- 
ceeded from the same part, and by the same 
road. I even suspect that both had been so- 
phisticated and mixed nearly one half with 
foreign crystalline and fenuginous rusty mat- 
ters, which are not to be met with in the natu- 
ral platina. 

4. The production of Prussian blue by pla- 
tina appears evidently to prove the presence 
of iron in those parts even of this mineral which 
are the least attractable to the magnet, and at 
the same time confirms what I have advanced 
on the intimate mixture of iron in its substance. 
The flowing of platina by spirits of nitre, also 
proves that although it has no sensible efferves- 
cence, this acid attracts the platina in an evident 

manner ; 

j&0 bvfjfon's 

irqiimcr ; and the authors who have asserted 
the contrary, have followed their common 
track, which consists in looking on all actions 
as iiiill which jdonot produce an cfFervcscence. 
These second experiments of the Conitc de, 
D.Iilly would appear to me very important, if 
they succeeded always alike. 

5., We mutt however admit that many es- 
sential points of inforrnat ion are wanting to pro- 
Tiounce affirrnativciv on the origin of platina. 
We know nothing of the natural history of 
his mineral, and we cannot top greatly exhort 
those wlio are able to examine it on the spot, 
to make known their observations; and until 
that is done we must confine ourselves to con- 
jectures, some of which appear only more pro- 
bable than oi hers. For example, I donotima- 
gine platina to be the work of man. The 
Mexicans and Peruvians knew how to ca^t 
and work gold before the arrival of the Spa- 
niards, and ihey were nut acquainted with iron, 
which nevertheless they must have employed 
in ^ great quantify. The Spuniards theiuj^ei V:es 
d'li^ not establish furnaces in tius countrywheii 
they first inhabited it to fuse iron. There 
is, therefore, every reason to conclude5 that 
th^y did not make use of the filings of iron 
for the separation qi gold, at least in the be- 


ginning of Iheir labours, v/hich does not go 
above two centuries and ^ halfback; a time 
much too short for so plentiful a production 
as platina, -which is found in large quantities 
in many places. 

Besides, uhen gold is mixed with iron, by 
fusing them together, we ma v always, by a 
chemical process, separate then), and extract 
the gold : Avhercas, hiihc-rto, chenaists have 
not been able to make this separation in pla- 
tina, nor determine the quantity of gold con- 
tained in this mineral. This seems to prove, 
tliat gold is united w ith it in a more intimate 
manner than the common alloy, and that iron 
is also in it, in a different state from that of 
common iron. Flatinn, therefore, appears to 
me to be the production of nature, and I am 
greatly inclined to think, that it owes it's first 
origin to the fire of volcanos. Burnt iron, 
intimately united Avithgoldby sublimation, or 
fusion, may have produced this mineral, whicli 
haying been at first formed by the action of the 
fiercest fire, will afterwards have felt tiie im- 
pression of water, and reiteraieil frictions, 
which have given it the form of blunt angles. 
But water alone might have produced platina ; 
for supposing gold and iron divided as much as 
possible by the humid mode, their molecules, 


1S2 buffonV 

bj unltin£^, will have formed the ^ains whicli 
compose it, and which from the heaviest to the 
lightest contain gold and iron ; the proposition 
of the chemist who offers to render nearly as 
much gold as they shall furnish him witlipla- 
tina, seems to indicate, that there is, in fact, 
only tV of iron to yt of gold in this mineral, 
or possibly less. But the nearly of this che- 
mist is perhaps a fifth, or fourth, and indeed, 
if he could realize his promise to a fourtli, it 
would be doing a great deal, and no vain boast. 

Being at Dijon the summer of 1773, the 
Academy of Sciences and Belles Letters, of 
which I have the honour to be a member, ex- 
pressed a desire of hearing my observations on 
platina ; and having complied, M. de Mor- 
veau resolved to make some exiK^riments on 
this mineral; for which purpose I gave him 
a portion of that which I had attracted by the 
loadstone, and also some which I had found 
insensible to magnetism, requesting him to ex- 
pose it to the strongest fire he could possibly 
make. Some time after, he sent me the fol- 
lowing experiments, which he was pleased to 
subjoin to mine. 

'*" Monsieur the Comtede Buffon, in a jour- 
ney to Dijon, in the summer of 1773, having 
caused me to remark in half a drachm of plati- 


na, which M. de Baume had sent hira in 17GS, 
grains in form of buttons, others flatter, and 
some black and scaly ; and having separated 
by the loadstone those which are attractable 
from those which appeared not so, I tried to 
form Prussian blue with botli. I sprinkled the 
fumin«: nitrous acid on the non-attractable 
parts, which weighed 2^ grains. Six hours 
after I put distilled water on the acid, and 
sprinkled alkaline liquor, saturated with a co- 
louring matter; however there was not a 
single atom of blue, the platina had only a 
little more brightness. I alike sprinkled the 
fuming acid on t!ie remaining platina, partof 
w hich was attractable, the same Prussian alkali 
precipitated a blue feculency, which covered 
the bottom of a pretty large bason. The pla- 
tina-, after this operation, shewed like the first. 
I washed and dried it, and found it had not lost 
I of a grain, or -^^-^ part ; having examined it 
in this state I perceived a grain of beautiful, 
yellow, which was pure gold. 

*' M. de Fourcy had lately told the world, 
that the dissolution of gold was thrown down 
in a blue precipitate by the Prussian alkali, 
and had placed this circumstance in a table of 
alfmity ; I was tempted to repeat this experi- 


184 SUFFON*** 

menf, and si3iinkled, in consequence, tlic 
plitogisticated alkaline liquor in fhe dissolution 
of gold, but the colour of this dissolution did 
not change, which made me suspect that the 
dissolution of gold made use of bj M. de 
Fourcy might possibly not have been so pure. 
" At the same time the Comte de Buffbn 
Laving given me a sufficient quantity of platina 
to make further assays, I undertook to separate 
it from all foreign bodies by a good front ; and 
I have here subjoined the processes and their 


*^ I. Having put a drachm of platina, in a 
cupel, into a furnace, I kept up the fire two 
hours, when the covers sunk down, the sup- 
porters having run, nevertheless the platina was 
only agglutinated ; it stuck to the cupel, and 
had left spots of a rusty colour. The pla- 
tina was then tarnished, even a little black, 
and had only augmented a quarter of a 
grain in weight; a quantity very small in 
comparison with that which other chemists 
have observed. AYhat surprised me still 
more was, that this drachm of platina, as well 
as that I used for other experiments, bad 
been successively carried away by the load- 


Uone, and made a portion of 4. of eight ounces, 
of \yhich the Comte dc Buiibn has before 
spoken . 

"II. II al f a d racli m of tlie same pi .itina , ex- 
posed to tlie same fire iii a cupel, wascilso ag- 
glutinated ; I adhered to thecnpel, on which it 
bad left soolsofa rusty colour; the augmenta- 
tion of weiglit was found to be nearly in the 
saniicproportioii, and the surface as black. 

*' iil. I put this half drachm into a new 
cupel, but ir.slead ot a cover I placed over it a 
leaden crucible. This I kept in the most ex- 
treme ijcat for four hours; y^hcti il was cooled 
I found tile crucible soldered to the supporf, 
and having broken it I perceived that nothing 
had peneirated into the internal part of the 
crucible, which appeared to be only more 
glossy than Uioie. The cupel had preserved 
its form and position ; it was a litile cracked, 
but not enough lo admit of any penetration ; 
the plalina was also not adherent to it, thouo-h 
agglutinated, but in a much more intimate 
manner than in the first experiments ; the 
grains were less angular, the colour more clear, 
^nd the brilliancy more metallic. But what 
was the most remarkable during the opera! ion 
there issued from its surface, probably in the 
first momenjts of its refrigeratioir, three drops 
VOL. X. B b ,,/ 


of water, one of wliich, that arose perfectly 
spherical, v/as carried up on a small pedicle of 
the vitreous and transparent matter. It was of 
an uniform colour, with a slight tint of red, 
which did not deprive it of any transparency ; 
the smallest of the other ( wo drops had likewise 
a pedicle, and the other none, hut was only at- 
tached to the plalina by its cxlcr:;ai surface. 

'' ly. I endeavoured to assay tlie platina, 
and for that intent put a drachm of the grains 
taken up by the loadstone into a cupel, with 
two drachms of lead. After havin<jc kept up 
a very strorig tire for two hours, I found an ad- 
herent butfon, covered with a yellowish and 
spungeous crust of two drachms twelve grains 
weight, which announces thattJie platina had 
retained one drachm twelve grains of lead. I 
put this button into another cupel in the same 
furnace, observii^g to turn it, by which it only 
lost twelve grains in two hours ; its colour and 
form were very little changed. The same 
piece of platina was put into Macquer's 
furnace, and a fire kept up for three hours, 
when 1 was obliged to take it out, because the 
bricks began to run. The platina was become 
more metallic, but it, nevertheless, adhered to 
the cupel, 'ud this time it lost 34 grains. I 
threw it into the fuming nitrous acid to assay it, 



and (here arising a li.tle cfFcrvcscpnce, I added 
distilled water (hereon. The platina lost two 
grains, and I remarked some small holes, like 
those which its flyinsf off might occasion. 

" There then remained only 22 grains of 
lead in the platina. I began lo form a hope of 
vitrifying this remaining portion of lend, for 
which purpose I put the s:ime piece of platina 
into a new cupel, and by the care I took for 
the admission of air. and other precautions, 
the activity of the fire Avas so greatly aug- 
mented that it required a supply every eleyen 
minutes; to this degree of heat we kept for 
four hours, and then permitted it to cool. 

" I perceived the next morning that the 
leaden crucible had resisted, and that the sup- 
})or<ers were only glazed by the cinders. I 
found a piece in the cupel, hot adhering, of 
a uniform colour, approaching more the colour 
of tin than any other metal, but only a little 
ragged. It weighed exactly one drachm. All, 
therefore, announced that this platina had en- 
dured an absolute fusion, and that it was per- 
fectly pure, for if we suppose it still contained 
lead, we must then admit that it had lost ex- 
actly as much of its substance as it had gained 
of foreign matter; and such a precision can- 
not be the effect of pure chance. 

" I passed 

1S8 kuffon's 

" I passed several days ^villl M. BufTon, 
whose company has the same charms as lib 
style, and whose conversation is as complete as 
his books : I took a pleasure in presenting him 
with the production of onr essays ; reexamined 
them together, and observed, First, that the 
drachm of platina, agglutinated by these ex- 
periments, was not attractable by the load- 
stone; that, nevertheless, the magnetical bar 
had an action on the grains that were loosened 
from it. 

'' 2, The half drachm of the third experi- 
ment was not only attractable in the mass, but 
the grains of gold separated therefrom did not 
themselves give any signs of magnetism. 

" 3. The platina of the fourth experiment 
was absolutely insensible to the loadstone. 

" 4. The specific weight of this piece was 
determined by a good hydroslatical balance, 
and being, for the greater certainty, compared 
to coined and to other very pure gold, used 
by M. BufFon in his experiments, their density 
was found, with water, in which they were 

Pure gold - 19 V 
Coin gold - 17 i 
Platina - 14 f 

" 5. This piece of platina was put upon 



etcel to try its dudability ; it supported the 
hammer verv well for a few strokes ; its sur- 
face because fiat and even, a little smooth in 
the parts which were struck, but it split soon 
after, and nearly a sixth part separated . The 
fracture presented many cavities, some of 
winch had the whiteness and brilliancy of 
silver, and in others we remarked several 
points like chrystalization ; the tops of these 
points examined with the lens, was a globule 
absolutely similar to that of the third experi- 
ment. All the other parts of this piece of 
platina were compact, the grain finer and 
closer than the best brass, which it resembled 
in colour. We offered several of these pieces 
to the loadstone, but not one was attracted 
thereby. We powdered them again in an 
ngate mortar, and then remarked that the 
magnetical bar raised up some of the smallcbt 
every time ihey are placed under it. 

" This new appearance of magnetism was 
so much the more surprising,as the grains were 
detached from the agglutin tied mass of the se- 
cond experiment, which seemed to have lost all 
sensibility at the approach and contact of the 
loadstone. In consequence we again took sonic 
of these grains, which were alike powdered, and 
soon perceived the smallest parts sensibly at- 
tach themselves to the magnetic bar. It is im- 

190 BUFFO n's 

possible to attribute this effect to the smdotfi-^ 
ness of the bar, or to any other cause foreign 
to magnetism. Apiece of smooth iron, ap- 
plied in the same manner on tlie parts of this 
platina did not raise up a single grain. 

" By tlyese experiments, and tlie observa- 
tions whicli ha ve arisen therefrom, we may judge 
of the diflFicuity of determining the nature of 
platina. It is very certain that it contains some 
parts which are vitrifiableeven without the ad- 
dition of a fierce fire ; it is also certain that all 
platina contains iron and attractable parts ; but 
ifthePrussian alkali never affords blue but with 
tlie grains which the loadsfone attracts, we 
should conclude, that those which resist it arc 
pure platina, which of itself hns no magnetical 
virtue, and of vvliich iron does not make an 
essential part* Wc must suppose that a suffi- 
cient fusion, or perfect cupcllation, might de- 
cide the question; at least, these operations 
appear to have, in fact, deprived it of every 
magnetic virtue, by separating it from all 
foreign bodies; but the last observation proves, 
in an incontrovertible manner, that this mag- 
netic property was, in realily, only weaken- 
ed, and perhaps masked or buried, since it re- 
appeared when it was ground.'' 

From these experiments of M. dc ivTorvean 
there results, 1. That we may expect to meet 



^latina without addition, by applying the 
fire of it several times successively, because the 
best crucibles might not resist the action of so 
fierce afire during the whole time that the 
complete operation would require. 

2. That by molting it with lead, and assay- 
ing them several times, we should in tlie end 
vitrify all the lead and the platina; and that 
this experiment would be able to purge it 
from a part of the ibrcign matters it contains. 

3. That by melting without any addition, 
it seems to purge itself partly into the vilres- 
cible matters it includes, since it emits to its 
surface sinall drops of glass, which form pretty 
considerable masses, and which we can easily 
sepamle after refrigeration. 

4. That by making experiments on Prussian 
blue with the grains of platina, which appeared 
to be most insensible to the lo-tdstone, v.e were 
not always certain of obtaining it ; a circum- 
stance which never fails with grains that have 
more or less sensibility to magnetism. 

5. It appears that neither fusion norcupella- 
tion can destroy all the iron with which platina 
is intimately penetrated; the pieces melted or 
assayed, appeared, in reality , equally insensible 
to the action of the load&tone; but having 
pounded them in a mortar, we found nurgnetical 

parts ; 

parts ; so mucbtlie more abwrrdaiit as the pla« 
tina was reduced to a fino powdtT. The first 
ptecr, whose grains were only aggUitinaled, 
b^ing ^^round, re»(]erecl many iiiiOic magrietical 
parts than tjie second and third, the grains of 
which hud undergone a stronger fusion ; but, 
ncvcrthek'ss, being both ground, they furnished 
magrtctical parts ; insomuch that it cannot be 
doubted liiat there is iron in platina, after it 
iias undergone the fiercest efilbrts of fire, and 
Ihse devouring actions of the heat in tlie cupel. 
This demoasirates, that this miuerdl is really 
an intiiBate mixture of gold and iron, whkli 
hitherto has not been able to separate. 

6. I made another observation with M. Mor- 
veau on melted, and afterwards on ground 
platina ; namely, that it takes in grinding pre- 
ctbely the same ibrm as it had before it had been 
iiielled ; all i he grains of this iiioKcd and ground 
platina are similar to those of the natural, as 
well in form as variety of size ; and they ap^ 
pear to differ only because the smallest alo»«4? 
jiufler themselves to be raised by ^he load.^tone, 
and in so much the less quantity as the platina 
has endured the nre. This seems also to prove, 
iluit, al hough the fire has been strowg enough 
itot oidy to l>in tvand vitrify, J>ut even to drive 
t)iiii \hiii of th^j iron^with other vitrescible 



mafter wliich it contains ; the fusion, never- 
theless, is not so complete as that of other per- 
fect metals, since, in grinding, it retakes the 
same figure as it had before fusion. 



THE story of the burning glasses of Archi- 
medes is famous ; he is said to have invented 
them for the defence of his country ; and he 
threw, say the ancients, the fire of the sun with 
such force on the enemy ^^ fleet, as to reduce 
it into ashes as it approached the ramparts of 
Syracuse. But this story, Avhich, for fifteen or 
sixteen centuries, was never doubled, lias been 
contradicted, and treated as fabulous in these 
latter ages. Descartes, with the authority of 
a master, has attacked this talent attributed to 
Archimedes; he has denied the possibility of 
the invention, nnd his opinion has prevailed 
VOL. X. C c over 

194; buffon's 

over the testimonies and credit of llicancienls. 
Modern naturalists, either through a respect 
for their philosopher, or through complaisance 
for their contemporaries, have adopted the 
same opinion. Nothing is allowed (o the an- 
cients but what cannot be avoided. Deter- 
nained, perhaps, by these motives, of ^vhich 
self-love too often is the abettor, have we not 
naturally too much inclination to refuse what 
is due to our predecessors? and if, in our 
time, more is refused than was in any other, 
is it not that, by being more enlightened, we 
think we have more right to fame, and more 
pretensions to superiority ? 

Be that as it may, this invention was the 
cause of many other discovoi i( s of antiquity 
which are at present unknown, because the 
facility of denying them has been preferred to 
the trouble of finding them out ; and the 
burning glasses of Archimedes have been so 
decried, that it does not appear possible to re- 
establish their reputation ; for, to call the 
the judgment of Descartes in question, some- 
thing more is required than assertions, and there 
only remained one sure decisive mode, but at 
the same time difficult nnd bold, which was 
to undertake to discover glasses that might 
produce the like effects. 



Though I had conceived the idea, I was for 
a long time deterred from making the experi- 
ment, from the dread of the difficulty which 
might attend it; at length, however, I deter- 
mined to search after the mode of makins: 
mirrors to burn at a great distance, as from 100 
to 500 feet. I knew, in general, that the power 
of reflecting mirrors, never extended farther 
than 15 or 20 feet, and with refringent, the dis- 
tance was still siiortcr : and I perceived it 
was impossible in practice to form a metal, or 
glass mirror, with such exactness as to burn at 
these great distances. To have sufhcient pow- 
er for that, the sphere, for example, must be 
800 feet diameter ; therefore, we could hope 
for nothing of that kind in the common mode 
of working glasses ; and I perceived also that 
if we could even find a new method to give to 
large pieces of glass, or metal, a curve suffi- 
ciently slight, there would still result but a 
very inconsiderable advantage. 

But to proceed regularly, it was necessary 
first to see how much light the sun loses by re- 
flection at different distances, and what are 
the matters which reflect it the stron^^^fst; I 
first found, ihii glasses when they are pjlished 
"with care, reflect the light more powiTlully 
than the best polished metals, aijd even bet- 

1D6 buffon's 

tcr tlian tho compounded metal with which 
■telescope mirrors are made ; and that although 
tliere are two reflectors in the glasses, they 
yet give a brighter and more clear light than 
metal. Secondly, by receiving the light of 
the sun in a dark place, and by comparing it 
w ith this light of the sun reflectpd by a glass, I 
found, that at small distances, as four or five 
feet, it only lost about half by reflection, 
%vhich I judged by letting a second reflected 
light fall on the first ; for the briskness of these 
two reflected lights appeared to be equal to 
ilmt of direct light. Thirdly, having received 
at the distances of 100, 200, and SOO feet, this 
light reflected by great glasses, I perceived 
that it did not lose any of its strength by 
the thickness of the air it had to pass 

I afterwards tried the same experiments on 
thelight of candles ; and to assure myself more 
exactly of the quantity of Aveakness that re- 
flection causes to »Iiis light, I made the follow- 
ing experiments . 

1 seated myself opi:oite a glass mirror with 
a book in mv hand, in a room where the dark- 
ness of the night would not permit me to dis- 
tinguish a single object. In an adjoining room 
I had a lighted candle placed at about 40 feet 

distance : 


x3istance ; this I approached nearer and nearer, 
till I could read the book, when the distance 
.was about 24 feet. Afterwards turning the 
book, I endeavoured to read by the reflected 
light, having by a parchment intercepted the 
part of the light which did not fall on the 
mirror, in order to have only the reflected 
light on my book. To do so I was obliged to 
approach the candle nearer, which I did by 
degrees, till I could read the same characters 
clearly by the same light, and then the distance 
from the candle, comprehending tliatofthe 
book to the mirror, which was only half a 
foot, I found to be in all 15 feet. I repeated 
this several times, and had always nearly the 
same results; from whence I concluded, that 
the strength, or quantity, of direct light is to 
that of reflected light, as 576 to 225 ; there- 
fore, the liglit of five candles reflected by a 
flat glass, is nearly equal to that of the direct 
light of two. 

The light of a candle, therefore, loses more 
by reflection than by the light of the sun ; and 
this difference proceeds from the rays of the 
former falling more obliquely on the mirror 
than the rays of the sun, which conic almost 
parallel. This experiment confirmed what I 
jbad at first found, and 1 hold it ccrtiiin, that 


irS buffon's 

the H:;lit of the sun loses only half by ils ic- 
flection on a glass mirror. 

This first information being acquired, I af- 
terwards sought what became of the images of 
the sun when received at great distances. To be 
perfectly understood we mustnot,as is generally 
done, consider the rays of the sun as parallel ; 
and it must also be remembered, that the 
body of the sun occupies an extent of about 
32 minutes ; that consequently the raj^ 
which issue from the upper edge of the disk, 
falling on a point of a reflecting surface, the 
ravs wliich i.%sue from the lower edfi:e falling 
albo on the same point of this surface, they 
form between them an angle of 32 minutes in 
the incidence, and afterwards in the reflection, 
and that, consequently, the image must in- 
crease in size in proportion as it is farther dis- 
tant. Atirntion must likewise be paid to the 
figure of those images ; for example, a plain 
square glass of half a foot, exposed to the rays 
of the sun, will form a square image of six 
inches, when this image is received at the dis- 
tance of a few feet ; by removing farther and 
farther off, the image is seen to increase, after- 
wards to become deformed, then round, in 
which state it remains still increasing in size, 
in proportion as we are more distant from the 
mirror. Thj^ image is composed of as many 



of the sun's disks as there are physical points 
in the reflecting surface; the middle point 
forms an image of the disk, (he adjoining points 
form the like, and of the same size, •which ex- 
ceed a little the middle disk: it is the same 
with the other points, and the image is com- 
posed of an infinity of disks, ^vhich surmount- 
ing regularly, and anticipating circularly one 
over the other, form the reflected image, of 
which the middle point of the glass is the cen- 

If the image composed of all these disks is 
received at a small distance, then their extent 
being soraewnat larger than that of the glass, 
this image is of the same figure and nearly of 
the same extent as the glass ; but when the 
image is received at a great distance from the 
glass, where the extent of the disks is much 
greater <han that of the glass, the image no^ 
longer retains the same figure as the glass, but 
becomes necessarily circular. To find the 
point of distance where the image loses its 
square figure, we have only to seek for the dis- 
tance wliere the glass appears under an angle 
equal to that the sun forms to our sight, i. e. 
an angrc of 32 minutes, and this di-tance will 
be that Vihere the image will lose its square 
ficnre, and become round, for the disks having 

al ways 

200 buffon's 

always an equal line to the semi-circle, whicK 
measures an ans^le of S2 minutes for a diame- 
ter, we shall find by this rule that a square 
glass of six inches loses its square figure at the 
distance of about 60 feet, and tliat a glass of 
a foot square loses it at 120 feet, and so on of 
the rest. 

By reflecting a li< tie on this theory we shall 
no longer be astonished to find, that at very 
great distances a large and small glass afford 
an image of nearly the same size, and which 
only differs by the intensity of the light ; we 
shall no longer be surprised that a round, 
square, long, or triangular glass, or any other 
figure, always yields round images* ; and we 
shall evidently see that images do not increase 
and lessen by the dispersion of light, or by 
any loss in passing- through the air, as some 
naturalists have imagined ; but that, on the 
contrary, it is occasioned by the augmentation 
of the disks, which always occupy a space of 52 
minutes to whatever distance they are removed . 

So, likewise, we shall be convinced, by 
the simple exposition of this theory, that 
curves, of any kind, cannot be used with ad- 
van! age 

* This is the Treason that the small images which pass 
betwixt the leaves of high and full trees, and which falling 
•n the walk* are all oval or round. 

T^ATURAL history; 201 

vantage to bum at a great distance, because the 
diameter of the focus can never be smaller than 
the chord, which measures an angle of 32 mi- 
nutes, and that, consequently, tlie most perfect 
concave mirror, whose diameter is equal to 
this chord, will never produce double the ef* 
feet of a plane mirror of the same surface ; and 
if the diameter of a curved mirror were less 
than the chord, it would scarcely have more 
effect than a plane mirror of the same surface. 
Wlien I had well considered the above I had 
no longer a doubt that Archimedes could not 
burn at a distance but with plane mirrors, for, 
independently of the impossibility they then 
felf, and which we feel at pleasure, of making /ifijlAi^ 
concave mirrors with so large a focus, I was 
well aware that the reflection I have just made 
could not have escaped this great raathemati- 
< ian . Besides, there is every reason to suppose 
that the ancients did not know how to make 
large masses of glass ; that tbey were ignorant 
of the art of burning it to make large glasses, 
possessing only the method of blowing it, and 
making bottles and vases; from which consi- 
deration I was led to conclude, that it was 
with plane mirrors of polished metals, and by 
the reflections of the sun, that Archimedes had 
been enabled to burn at a distance. But as I 
VOL. X. D d perceived 

202 ; buffon's 

perceived iliat glass mirrors reflected the 
light more powerfully than the most polished 
mirrors, I thought to construct a machine to 
coincide iu the same point the reflected images 
by a great number of these plane glasses, be- 
ing well convinced that this was the soic 
mode of succeeding. 

Nevertheless, I had still some doubts re- 
maining, which appeared to me well founded, 
for thus I reasoned. Supposing the burning 
distance to be 240 feet, I perceived clearly 
that the focus of ray mirror could not have a 
less than two feet diameter; in which case 
what would be the extent I should be obliged 
to give to my assemblage of plane mirrors to 
produce a fire in so great a focus ? It might be 
so great that the thing would be impracticable 
in the execution, for, by comparing the dia- 
meter of the focus to the diameter of the mir- 
ror, hi the best reflecting mirrors, I observed 
that the diameter of the Academy's mirror, 
which is three feet, was 108 times bigger than 
its focus, which was no more than four lines ; 
and I concluded, that io burn as strong at 
240 feet it was necessary that my assemblage 
of mirrors should be 216 feet diameter tohavea 
focus of two feet; now a mirror of 216 feet 
diameter was certainly an impossible thing. 



This mirror of Uiree feet diamcier burnt 
strong enough to melt gold, and I wasdcsiroa 
to see how much I should gain -by reducing 
its action to the burning of wood. For this 
purpose I used circular zones of paper on the 
mirrors to diminisli the diameter, and I fuund 
that there was no longer power enough to in- 
flame dry wood when its diameter was reduced 
to Kttle more than four inches ; therefore, tak- 
ing five inches, or sixty lines, for the diameter 
necessary to burn with a focus of four lines, 
it appeared, that to burn equally at 210 feet, 
where the focus should necessarily bave two 
feet diameter, I should require a mirror of 30 
feet diameter, which appeared still as impossi- 
ble, or at least impracticable. 

To such positive conclusions, and which 
others would have regarded as demonstrations 
of the impossibility of the mirror, I had only a 
supposition to oppose; but an old supposi- 
tion, on which the more I reflected the morei 
was persuaded that it was not without founda- 
tion ; namely, that the effects of heat might 
possibly not be in proportion to the quantity 
of light, or, what amounts to the same, that 
at an equal intensity of light large focuses 
must burn brisker than the small. 
By estimating heat mathematically, it is not 


204 BUFFO n's 

to be doubted but that the power of a focus of 
the same length is in proportion to the surface 
of the mirror. A mirror whose surface is dou- 
ble that of another, must have the same sized 
focus, and this focus must contain double the 
quantity of light which the first contained ; 
and in the supposition, that eftects are always 
in proportion to their causes, it might be pre- 
sumed that the heat of this second focus should 
be double that of the first. ^ 

So likewise, and by the same mathe^aticiil 
estimation, it has always been thought, that at 
an equal intensity of light, a small focus ought 
to burn as much as a large one, and that the 
eifect of the heat ought (o be in proportion to 
this intensity of light : insomuch (says Des- 
cartes J that glasses^ or extremely small mirrors, 
may he made^ which will burn with as muchxio- 
lence as the large, I at first thought tliat this 
conclusion, drawn from mathematical theory, 
might be found false in practice, because heat 
being a physical quality, of the action and 
propagation of which we know not the laws, 
it seemed to me, that there was some kind of 
temerity in thus estimating its effects by a sim- 
ple speculation. 

I had, therefore, once more, recourse to 
experiments. I took metal mirrors of differ- 


cnt focuses and dificrent dei^rees of polisb, and 
by compnrins; the diffiirent actions on (he 
same fusible or combustible raniters, I foujtJ, 
that at an equal intensify of ii:rh/, large focuses 
constantly have more effect than small, and I 
discovered the same to be the case ^yiih refract- 
ing mirrors. 

It is easy to assign the reason of this differ- 
ence, if we consider that hcai coninsunica^cs 
nearer and nearer, and disperses, if I rsiay 
so speak, when it is even applied on the same 
point: for example, if wc let the focus of a 
burning glass f:dl on the cenfrc of a crown 
piece, and that this focus was only a line in 
diameter, the heat produced on the centre 
disperses and extcn(!s over and throughout the 
whole piece : thus alt the heat, although used 
at first to the centre of the crown, does not stop 
there, and consequently cannot produce so 
great an eff'^ct cis if it did. Bat if, iiisiead of 
a focus of aline v.^hich falls upon the centre of 
the crov/n, we let tall a focus of equal intensity 
on the whole crown, every jjart being alike 
heated, then instead of experiencing the less 
heat, it acquires an augmentation ; for the 
middle profiting of the heat with the other 
points which surround i(, the crown piece 


206 BUFFO n'^S 

will be melted in this laltercasc, "while in the 
first, it will only be slightly heated. 

After these experiments and reflections, I 
began to entertain sanguine hopes of making 
mirrors to burn at a great distance; for I no 
ionger dreaded as before, ihc great extent of 
the focus; I was persuaded, on the contrary, 
that a focus of a considerable breadth, as4\^ 
feet, and which in the intensity of the light 
would not be near so great as in a small 
focus of four lines, might, nevertheless, pro- 
duce inflammation, and with more power ; 
and that, consequently, this mirror, which, 
hy mathematical theory, ought to iiave at 
least thirty feet diameter, would be reduced 
to one of eight or ten feet at most, which was 
not only a possible, but even a very practical 
ble thing. 

I then thought seriously of executing my 
project: I had at first a design of trying to 
burn at iOO or 300 feet distance with circular 
or hexagonal glasses of a square foot in surface, 
and I was desirous of having four iron car- 
riages for them, with screws to each to move 
them, and a spring to adjust tliem; but the 
considerable expense that this required made 
roe quit that idea, and I took two common 
glasses of six inches by eight, and a wooden 



atljustment, which, in fact, was less solid and 
precise, but the expence was more consistent 
with a mere experiment : the mechanism of 
"which was executed by M. Passement. 

It is sufficient to say, that it was at first 
composed of 168 glasses of six inches by 
eight each, about four lines distant from 
each other; these glasses moved in all direc- 
tions, and the four lines of space between them 
not only served for the freedom of this motion, 
but also to let the operator see the place where 
lie was to conduct his images. By means of 
this construction, 168 images could be thrown 
on one point, and, consequently, burn at se- 
veral distances, as at 20, SO, and to 150 feet. 
By increasing the size of the mirror, or by 
imiking other mirrors like the first, we are cer- 
tain of throwing fire to still greater distances, 
or to increase as much as we please the force 
or activity of those first distances. 

It is only to be observed, that the motion 
here spoken of is not very easy to be executed, 
and that also there is a very great choice to be 
made in the glasses ; for they are not all equally 
good, though they appear so at the first in- 
spection. I was obliged to pick out of more 
than 500 the 168 I made use of. The method 
of tr} ing thera is to receive at 150 feet distance 
j^c reflected image of the sun, as a vertical 

plane ; 


plane ; we must select those wliiclj give a round 
and terminated image, and reject those, 
•whose thickncvsscs being unequal in difFerent 
parts, or the surface a little concave or con- 
vex, have images badly terminated, double, 
treble, oblong, &c. according to the different 
defects found in the glasses. 

Bj the first experiment which I made the 
23d of March, 1747, at noon, I set fire to a 
plauk of fir at 6(ifeet distance, with 40 glasses 
only, about a quarter of the mirror. It must 
be observed (hat not being yet mounted, it was 
very disadvantageously placed, forming an 
angle with the sun of twenty degrees declina- 
tion, and another of more than ten degrees in- 

Tlie same day I set fire to a pitchy and sul- 
phureous plank at 126 feet distance, with 
eighty-eight glasses, tlie mirror being s(iU 
placed disadvantageously. It is well known, 
that to burn with the greatest advantage tlie 
mirror should be directly opposed to the sun, 
as well as the matters to be inflamed ; so that, 
by supposing a perpendicular plane on the 
plane of the mirror, it must pass by the sun, 
and, at Ihc same time, through the midst of 
combustible matters. 

The 3d cf ^\pril, at four o^clock in the af- 
ternoon, the mirror being mounted, produced 

a sliiiht 


tt slight inflaramad'on on a plank covered with 
pilch at 138 feet distance, although the sun 
"was weak and the light pale. Great care 
must be taken, when we approach the spot 
where the combustible matters are, not to 
look on the mirror ; for if, unfortunately, the 
eyes should meet the focus, inevitable blind- 
ness will ensue* 

The 4th of April, at cloven in the morning, 
although the sun appeared watery, and the sky 
cloudy, yet it produced, with 154 glasses, so 
considerable a heat at 158 feet, that in less than 
two minutes it made a deal plank smoke^ 
and ^vhich wouldccrtainiy have flamed, if the 
sun had not suddenly disappeared . 

The ensuing day, the 5th of April, at three 
o'clock in the afteraoon, we set fire, in a minute 
a'ld a half,at 150 feet distance, to a plank sul- 
phured and mixed with coals. with 154 glasses. 
When the sun is powerful, only a few seconds 
is required to produce inflammation. 

The lOih of April in the afternoon, the sun 
being bright, we set fire to a fir plank at ]oQ 
feet distance, with only 128 glasses : the in- 
flammation was very sudden, and made in all 
the extent of the focus, which was about six- 
teen inches diameter at this distance. 

The same day, at half past t vo o'clock, W0- 
threw the fire on another plank, partly pitched 
VOL. X. E e ?ii 

210 BUfFO>f s 

and covered with sulphur in some places : the 
infla'ramation was made very suddenly; it be- 
gan by the parts of the wood whi^h were un- 
covered, and the fire was so violent, that the 
plahk was obliged to be dipt in water to ex- 
tinguish it : there were 148 glasses at 150 feet 

The eleventh of April, the focus being only 
20 feet distant from the mirror, it only required 
12 glasses to inflame small combustible matters; 
with 21 glasses we set fire to another plank 
which had already been partly burnt ; with 
45 glasses we melted a block of tin of 61b. 
weight ; and with 117 glasses we melted thin 
pieces of silver, and reddened an iron plate ; 
imd I am also persuaded, that by using all the 
glasses of the mirror we should have been en- 
abled to have melted metals at 50 feet dis* 
tance ; and as the focus at this distance was 
six or seven inches broad, we should be aWe to 
make trials on all metals, which it was not 
possible to do with common mirrors, whose 
focus is either very weak or 100 times smaller 
than that of mine. I have remarked, (that me^ 
tals, and especially silver, smoke much before 
they melt ; the smoke was so striking that it 
shaded the ground, and it was there I looked 
on it attentively, for it is not possible tdlook a 
moment on the focus when it falls on the me- 


taij (he lustre being much more dazzling tliaii 
that of the sun. 

Tiie experiments which I have here related, 
^nd which were made immediately after the 
invention of the mirrors, have been followed 
by a great number of others, which confirm 
them. I liave set fire to wood at 210 feet dis- 
tance with this mirror, by (he sun in summer ; 
and I am certiiin, that with lour similar mir- 
rors I could buri at 400 feet, and, perliaps, 
at a greater di4rince. I have likewise,melt- 
ed all metals, and metallic minerals, at S5, 
SO, and 40 feei. We sliall find, in the course 
of this article, tlje uses to which these mirrors 
can be applied, and the limits that must be 
assigned to their power for calcination, com- 
bustion, fusion, &c.* 

This mirror burns according to the different 
inclination given it, and what gave it this ad- 
vantage over the common reflecting mirrors 
was that its focus was very distant, and had 
so little curvature, that it was almost imper- 
ceptible : it was seven fe»t broad by eight 
feet high, which makes about the IjOlh part 
of the circumference of the sphere, when we 
burn at 150 feet distance. 


* It requires about half an hour to mount the mirror and 
to make all the images fall on the same point ; but wJien 
this is once adjusted, it may be used at all times by simply 
drawings curtain. 

212 buffonV 

- The reason (liat detcrminccl me to prefer 
glasses of six inches broad by eight inches 
high to square glasses of six or eight inches, 
^vas, th;it it is much more commodious to 
make experiments npon a horizontal and level 
ground than otherwise, and that with this fi- 
gure,thc height of which exceeded the breadth, 
the images were rounder ; whereas with square 
glasses they would be shortened, especially at 
small distaucrs, in a horizontal situation. 

This discovery furnishes us with many useful 
hints for physic, and periiaps for tlie arts. We 
know that v.Jiat renders common reflecting 
mirrors most useless for experiments is, that 
they burn almost always upwards, and tliat we 
are greatly cmbarrafsed to find means to sus- 
pend or !juppoit to their focus matters to be 
melted or c^dcined. By means of my mirror we 
burn concave mirrors downwards, and with so 
great an advantage that we have what degree 
of heat v/e please ; for example, by opposing 
to my mirror a concave one of a foot square in 
the surface, the lieat produced to this last mir» 
ror, by using 154 glasses only, will be upwards 
of 12 i lines greater than that generally pro- 
duced, and the viWct will be the same as if 12 
suns existed instead of one, or rather as if t!ic 
sun had 12 times more heat, 



Seconclly, By means of my miiTor we shall 
bave the true scale of tiic augmentation of heat, 
and make a real thermometer, whose divisions 
will be no lonsjer arbitrary, from the tempera- 
ture of the air to what degree of heat we chiise, 
by letting fall, successively, the images of the 
jBun one on the other, and by graduating the 
intervals, whether by means of an expansive 
liquor, or a machine of dilatation, and from 
that we shall know, in fact, what a double, 
treblc.quadruple, &c. augmentation of heat is, 
and shallfind out matters whose expansion, or 
other effects, will be the most suitaJjie to mea- 
sure the augmentations of heat. 

Thirdly, We shall exactly know how many 
limes is required for the heat of the sun to 
burn, melt, or calcine different matters, which 
was hitherto only known in a vague and very 
indefinite lyauner ; and shall be in a state tr> 
make precise compariisons of the activity of our 
fires with that of the sun, and have exact rela- 
tions and fixed and invariable measures. In 
short, those who examine my theory, and shall 
^avcseen the effect of my mirror. I think will 
be convinced the mode I have used was the 
only one possible to succeed to burn f^r off, 
^or, inJependant of the physical difticulty of 


making large concave, spherical; parabolical 
mirrors, or of any atUer curvature whatsoeverj 
regular enough to burn at 150 feet distance, 
we shall easily be convinced that they would 
not produce but nearly as rmich effect as mine, 
because the focus would be almost as broad ; 
that besides, these curved n)irrors, if even it 
should be possibl to make them, would have 
the very great disadvanlagc to burn only at a 
mgh distance, whereas mine burns at all dis- 
tances ; and, consequently, we shall abandon 
the scheme of making mirrors to burn at a 
^reat distance by means of curves, which has 
uselessly employed a great number of mathe- 
maticians and artists, who were always de- 
ceived, because they considered the rays of Ih© 
sun as parallel, w hereas they should be consi- 
dered as they are, namely, as forming angles of 
all sizes, from to 32 minutes, which makes 
it impossible, wliatsoevcr curve is given to a 
mirror, to render the diameter of the focus 
smaller than the chord, which measures S2 
minutes. Thus, even if we could nmke a 
concave mirror to burn at a great distance ; 
for exam pie, at 150 feet, by employing all its 
points on a sphere of COO f^ci diameter, and 
by employing an uncommon mass ofghiss or 



metal, it is evident that we shall have a little 
more advantage than by using, as I have done, 
only small plane mirrors. 

On(!ic whole, alflunugh this mirror is sus- 
ceptible of a very gre:;! perfection, both for 
the adjustment, and many other particulars, 
and though I think I shall be able to make 
another, whose effects will be superior, yet, as 
every thing has its limits, it must not be ex- 
pected that every one can be formed to bur a 
at extreme distances ; to burn, for e:5ample, 
at the distance of half a mile, a mirror 200 
times larger would be required ; and I am of 
opinion that more will never be effected thaa 
to burn at the distance of 8 or 900 feet. The 
focus, whose motion is always correspondent 
to that of the sun, moves so much the quicker 
as it is farther distant from the mirror ; and at 
90 feet it would move about six feet a minute. 

[lowever, as I have given an account of my 
discovery, and the success of my experiments, 
I should render to Archimedes, and the an- 
cients, the glory that is their due. It is certain 
that Archimedes could |">erforin witii metal 
mirrors what I have done with glass, and that, 
consequently, I cannot refuse him the title of 
the first inventor of these mirrors, and !he op- 
portunity he had of using them rendered him, 


SI 6 BUFFO N^gr 

without doubt, more celebrated than the merti 
t)f the thing itself. 

Many advanlagcs may be derived from the 
use of these mirrors ; by an assemblage of 
small mirrors^ with hexagonal planes, and po-* 
lished steel, which will have more solidity than, 
glasses, and which would not be subject to the 
alterations which the liglit of ihe sun may 
cause, we may produce very useful effects, 
and which would amply repay the expences 
of the construction of the mirror^ 

" For all evaporations of salt waters, wliere 
great quantities of wood and coal are consumed^ 
or structures raised for the purpose of carrying 
the waters off, which cost more than the con- 
struction of many mirrors, such as I mention > 
for the evaporation of salt waters, only an as- 
semblage of twelve plane mirrors of a square 
foot each is necessary. The heat reflected by 
their focuses, although directed below their 
level, and at tifteea or sixteen feet distance, will 
be still great enough to boil water, and conse- 
quently produce a quick evaporation : for the 
lieat of boiling water is only treble the heat of 
the sun in summer; and as the reflection of a 
well polished plane surface only diminishes the 
heat one half, only six mirrors are required to 
produce at the focus a heat equal to boiling 

water j 


^ater ; but I shall double the number to make 
the heat communicate quicker; and likewise by 
reason of the loss occasioned by the obliquity, 
under which the light falls on the surface of the 
water to be evaporated, and because salt water 
heats slower than fresh. This mirror, whose 
assemblage would form only a square four feet 
broad by three high, would be easy to be 
managed ; and if it were required to double or 
treble the effects in the same time, it would be 
better to make so many similar mirrors, than 
to augment the scale of them; for water can 
only receive a certain quantity of heat, and we 
should not gain any thing by increasing this 
degree; whereas, by making two focuses with 
two equal mirrors, we should double the effect 
of the evaporation, and treble it by three mir- 
rors, whose focuses would fall separately one 
from the other on the surface of the water to 
be evaporated . We cannot avoid the loss caus- 
ed by the obliquity ; nor can it be remedied 
but by suffering a still greater, that is, by re- 
ceiving the rays of the sun on a large glass, 
which would reflect them broken on the mirror; 
for then it would burn at bottom instead of the 
top, but it would lose half the heat by the first 
reflection, and half of the remainder by the 
second ; so that instead of six small mirrors, it 
VOL. X. F f ^ould 

218 buffon's 

\vould require a dozen to obtain a lieat equaf 
to boiling water. For the evaporation to be 
made with more success, we ought to diminish 
the thickness of the water as much as possible ; 
a mass of water a foot deep will not eva* 
|)Grate nearly so quick as the same mass re- 
duced to six inches, and increased to double the 
superfices. Besides, the bottom being nearer 
the surface, it heats quicker, and this heat, 
which the bottom of the vessel receives, con- 
tributes still more to the celerity of fhe eva- 

2. These mirrors may be used with advan- 
tage to calcine plaislcrs, and even calcareous 
stones, but they would require to be larger, and 
the matters placed in an elevated situation, that 
nothing might be lost by the obliquity of the 
light. It has already been observed that gyp- 
sum heats as soon again as soft calcareous stone, 
and nearly twice as quick as marble, or hard 
calcareous stone ; their calcination, therefore, 
Jnust be in a respective ratio. I have found 
by an experiment repeated three times, that 
very little more heat is required to calcine 
white gypsum, called alabaster, than to melt 
ieati. Now the heat necessary to melt lead is, 
according to the experimentsof Newton, eight 
limes stronger than the heat of the summer 
^un ; it therefore would require at least six- 



teen small mirrors to calcine gypsum ; and 
because of the losses thereby occasioned, as 
:weU by the obliquity of the light as by the 
inequality of the focus, which is not removed 
above fifteen feet, I presume it would require 
twenty, and perhaps twenty-four mirrors of a 
foot square each, to calcine gypsum in a short 
4ime, consequently it would require an assem- 
blage of forty -eight small mirrors to calcine 
^he softest calcareous stone, and seventy-two 
of a foot square to calcine hard calcareous 
stones. Now a mirror twelve feet broad by 
«ix feet high, would be a large and cumber- 
some machine ; yet we might conquer these 
difficulties if the product of the calcination 
were considerable enough to surpass the ex- 
pense of the consumption of wood. To as- 
certain this, we ought to begin by calcining 
plaister with a mirror of twenty-four pieces, 
and if that succeeded, to malce two other si- 
milar mirrors, instead of making a large one 
of seventy-two pieces ; for by coinciding ihe 
focuses of these three mirrors of twenty-four 
pieces, we should produce an equal heat, 
strono- enough to calcine marlie or hard stone. 
But a very essential matter remains doubtful, 
that is, to know how much time would be re- 
quisite, for example, to calcine a cubical foot 
^ matter, especially if that foot were struck 


220 BUFFO n's 

with llie heat only in one part. Some time 
would pass before the heat penetrated its thick- 
ness; during this time, a great part of the 
heat would be lost, and which would issue 
from this piece of matter after it had entered 
it. I fear, therefore, much that the stone not 
being touched by the heat on every side at 
once, the calcination would be slower, and the 
produce less. Experience alone can decide 
this, but it would be at least necessary to at- 
tempt it on gypsous matters, whose calcina- 
tion is as quick again as calcareous stone. 

By concentrating this heat of the sun in a 
kiln, which has no other opening than what 
admits the light, a great part of the heat 
would be prevented from flying off, and by 
mixing with calcareous stone a small quan- 
tity of coal dust, which is the cheapest of all 
combustible matters, this slight supply of food 
would suffice to feed and augment the quan- 
tity of heat, which would produce a more 
ample and quick calcination, and at very little 

3. These mirrors of Archimedes might be, 
in fact, used to set fire to the sails of vessels, 
and even to pitched wood at more than 150 
feet distance ; they might also be used against 
the enemy, by burning tbe grain and other 
productions of tlie earth ; this eifcct would be 



no less sudden than destructive ; but we will 
not dwell on the means of doing mischief, 
conceiving it to be more our duty to think on 
those which may do some real service to man- 

4. These mirrors furnish the sole means of 
exactly measuring heat. It is evident that U\o 
mirrors, whose luminous images unite, produce 
double heat in all tiie points of their surfaces, 
that three, four, five, or more mirrors, will 
also give a treble, quadruple, quintuple, &c. 
Leaf, and that, consequently, by this mode we 
can make a thermometer whose divisions w ill 
not be too arbitrary, and the scales different, 
like those of tlic present thermometers. The 
only arbitrary thing which would enter into 
the composition of the thermometer, would be 
the supposition of the total number of the parts 
of the quicksilver by quitting the degree of 
absolute cold: but bv takins; it to lOO'uO be^ 
low the congelation of water, instead of 1000, 
as in our common thermometers, we should 
approach greatly towards reality, especially 
by chusing the coldest day in winter to mark 
the thermometers, for then every image of the 
sun would give it a degree of heat above the 
temperature of ice. The point to which the 
mercury rises by the first image of the sun, 
•would be marked 1, and so on to the highest, 


222 BUFFO n's 

which might be extended to 35 degrees. * At 
this degree we should have an augmentation of 
heat, thirty-six times greater than that of the 
first, eighteen times greater than that of the 
second, twelve times greater than that of the 
third, nine times greater than that of the 
fourth, and soon ; this augmentation of thirty- 
six of heat above that of ice would be sufficient 
to melt lead; and there is every appearance 
to think that mercury, which volatilizes by a 
much less heat, would by its vapour break the 
thermometer. We cannot therefore, at most, 
extt^nd the division farther than twelve, and 
perhaps not farther than nine degrees, if mer- 
cury be used for these thermometers, and by 
these means we shall have only nine degrees of 
the augmentation of heat. This is one of the 
reasons which induced Newton to make use of 
linseed oil instead of quicksilver; and, in fact^ 
hy making use of this liquor, we can extend 
the division not only to twelve degrees, bot as 
far as to make this oil boil. I do not pro- 
pose spirits of wine, because that liquor de? 
composes in a very short time, and cannot be 
used for experiments of a strong heat.* 


• Many travellers have tol4 and written to me, that Reau- 
mur's thermometers of spirit of wine, became quite useless 
to th€m, because this liquid lost its colour, and became 
charged with a sort ©f mud in a very short time. 


%Vhen on the scale of these thermometers 
filled with oil or mercury, the first divisions 
1, 2, 3, 4, &c. are marked to indicate the 
double, treble, quadruple, &c. augmentations 
of heat, we must search after the aliquot parts 
of each division ; for example, of the point 1|, 
^i, SI, &c. or I|, 2f , Sf, &c. and 1|, 2|, Sf, 
and which will be obtained in an easy manner, 
by covering the |,|, or |, of the superficesof 
one of those small mirrors ; for then the image 
-which it reflects, will contain only the |, |, or f , 
of the heat which the whole ima<re will con- 
tain, and, consequently, the division of the 
aliquot parts will be as exact as those of the 
whole numbers. 

If once we succeed in this real thermometer, 
Tvhich I call real, because it actually marks 
the proportion of the heat, every other thermo- 
meter whose scale is arbitrary and different, 
will become not only superfluous, but even 
inimical, in many cases, to the precision of na- 
tural truths sought after by these means. 

5. By means of three mirrors we may easily 
collect in their entire purity, the volatile parts 
of gold, silver, and other metals and minerals ; 
for, by exposing to the large focus of those 
mirrors a large piece of metal, as a dish, or 
silver plate, we shall see smoke is-^ue from it 



in great abundance, and for a considerable 
time, till the metal is in fusion ; and by giving 
only a smaller heat than what fusion requires, 
we shall evaporate the metal so as to diminish 
the weiglit considorably. 

I am certain of this circumstance, which 
also elucidates the intimate composition of 
metals. I was desirous of collecting this plen- 
tiful vapour, which the pure fire of the sun 
causes to issue from metal, but I had not the 
necessary instruments, and I can only recom- 
mend to chemibts and naturalists to follow this 
important experiment, the results of which 
would be as much less equivocal as the metallic 
vapour is pure ; whereas, in all like operations 
made with common fire, the metallic vapour is 
necessarily mixed with other vaj:ours proceed- 
ing from combustible matters, which serve for 
food to this fire. 

Besides, this means is the only one we have 
to volatilize fixed metals, such as gold and sil- 
ver ; for I presume that this vapour, which I 
have seen rise in such great quantities from 
these fixed metals, heated in the large focus of 
my mirror, is neither of water, nor of any 
other liquor, but of the parts even of the me- 
tal which tile heat detaches by volatilizing 
them. By receiving these vapours of different 


NATURAL insTonv. 225 

metals J and thus mixing them together, more 
intimate and pure alloys would be made thaa 
can be by fusion, and the mixture of these me- 
tals when melted, which never perfeclly unites 
on account of the inequality of their specific 
weight, and many other circumstances which 
are opposed to the intimate and perfect equality 
of the mixture. As the constituent parts of 
the melallic vapours are in a much greater 
state of division than fusion, th-y would join 
and unite closer and more readily. In shorty 
we should attain the knowledge of a general 
fact by this mode, and which, for many rea- 
sons, I have a long time sust ec(ed, that there is 
penetration in all alloys made in this manner, 
and that their specific weight would be alwavs 
greater than the sum of the specific > eights of 
the matters of which they are composed : for 
penetration is only a greater degree of inti- 
macy; every thing equal in other respects will 
be so much the greater as matters will be in a 
more perfect state of division. 

By reflecting on the vessels used to receive 
and collect these metallic vapours, I was 
struck with an idea, which apjeared to me to 
be of too great utility not to publish ; i( isako 
easy enougli to be realized by good able che- 
mists ; I have even communicated it to some 
VOL. X. G g of 

^26 buffon's 

of them, wbo appeared lo be quite satisfied 
■with it. This idea is to freeze mercury in this 
climate, and with a much less degree of cold 
than that of the experiments of Petcrsburgh 
or Siberia. For this purpose the vapour of 
mercury is only required (o be received, and 
"which is the mercury itself volatilized by a 
very moderate heat in a crucible, or vessel^ to 
which we give a certain degree of artificial 
cold. This vapour, or this mercury, minutely 
divided, will offer, to the action of the cold, 
surfaces so large, and masses so small, that in- 
stead of 187 degrees of cold requisite to freeze 
mercury, possibly 18 or 20 will be sufficient, 
and perhaps even less to freeze it when in va-? 
pour. I recommend this important experi- 
ment to all those T\ho endeavour earnestly for 
the advancement of the sciences. 

To these principal uses of the mirror of 
Archimedes, I could add many other particular 
ones; but L have confined myselfto those only 
which appeared the most useful, and the least 
difficult to be put in practice ; neyertheless I 
have subjoined some experiments that I made 
on thetransmission of light through transparent 
bodies, to give some new ideas on the means of 
seeing objects at a distance witli the raked eye, 
pr with a mirror, like lluit spoken of by the an^ 



cientsi and hyihe eifectof vvliicli vessels could 
be perceiv ed from the port of Alexander, as 
far as the curvature of the earth would permit. 
Naturalists at present know, that there are 
three causes which prevent the light from 
uniting in a point, when its rays have passed 
the objective glass of a common mirror. The 
first is the spherical curve of this glass, wliicli 
disperses a part of the rays in a space termi- 
nated by a curve. Tlie second is the angle 
under which the object appears to the naked 
eye : for the breadth of the focus of the ob- 
jective glass has a diameter nearly equal to 
the chord of which this angle measures. The 
third is the different refrangibility of the light ; 
for the most refrangible rays do not collect in 
the same place with the lesser. 

The first cause may be remedied by substi- 
tuting, as Descartes has proposed, elliptical, or 
liypcrbolical, glasses to the spherical. The 
second is to be remedied by a second glass, 
placed to the focus of the objective, whose 
diameter is nearly equal the breadth of this 
focus, and whose surface is worked on a sphere 
of a very short ray. The third has been found 
to be remedied, by making telescopes, called 
Acromatics, which are composed of two sorts 
of glasses, which disperse the coloured rays 

differently 5 


differently : so that the dispersion of the one 
is corrected by tlic other, without the general 
refraction, which constitutes the mirror, being 
destroyed. A telescope Sf feet long, made on 
this principle, is in effect equivalent to the old 
telescopes of 25 feet. 

But the remedy of the first cause is perfectly 
useless Jit this time, because the effect of the 
last being much more considerable, has such 
great influence on the whole effect, that nothing 
can be gained by substituting hyperbolical, or 
elliptical glasses to spherical, and this substi- 
tution could not become advantageous, but in 
the case where the meaiis of correcting the 
effect of the different refrangibility of the rays 
of light might be found ; it seems, therefore, 
tliat we should do well to combine tlie two 
means, and to substitute, in acromatic teles- 
copes, elliptical glasses. 

To render this more obvious, let us suppose 
the object observed to be a luminous point 
wilhout extent, as a fixed star is to us. It is 
certain, that with an objective glass, for ex- 
ample, of SO feci focus, all the images of this 
luminous point will extend in the form of a 
curve to this focus, if it be worked on a sphere; 
and, on tlie contrary, ihcy will unite in one 
pi'intif this gla^s be hyperbolical : but if the 



object observed have a certain extent, as the 
moon, which occupies half a degree of space 
1o our eyes, then the image of this object will 
occupy a space of three inches diameter in the 
focus of the objective glass of thirty feet ; and 
the aberration caused by the sphericity pro- 
ducing a confusion in any luminous point, it 
produces the same on every luminous point of 
the moon's disk, and, consequently, wholly 
disfigures it. There would be, then, much 
disadvantage in making use of elliptical glasses 
or long telescopes, since the means have been 
found, in a great measure, to correct the effect 
produced by the different refrangibility of the 
rays of light. 

From this it follows, that if we would make 
a telescope of SO feet, to observe the moon, 
and see it completely, the ocular glass must be 
at least three inches diameter, to collect the 
whole image which the objective glass pro- 
duces to its focus ; and if we would observe this 
planet with a telescope of 60 feet, the ocular 
glass must be at least six inches diameter, be- 
cause the chord which the angle measures 
under which the moon appears to us, is, in 
this case, nearly six inches; therefore astro- 
nomers never make use of telescopes that in- 
clude the whole disk of the moon, because 
they would magnify but very little. But if 


550 BUFFO n's 

we would observe the planet Yen us witli a te- 
lescope of 60 het^ as the angle under which it 
appears to us is only CO secondsj the ocular 
glass can only have four lines diameter ; and 
if we make use of an objective of 120 feet, an 
ocular glass of eight lines diameter would suf- 
fice to unite the whole image which the ob- 
jective forms to its focus. 

Hence we see, that even if the rnjs of light 
were equally refrangible we could not make 
such strong telescopes to see the moon with as 
to see the other planets, and that the smaller a 
planet appears to our sight the more we can 
augment the length of the telescope, with 
which wc can see it wholly. Hence it may be 
well conceived, that in this supposition of the 
rays, equally refrangible, there must be a cer- 
tain length more advantageously determined 
than any ether for each different planet, and 
that this length of the telescope depends not 
only on the angle under whicli the planet ap- 
pears to our sight, but also on the quantity of 
li£:ht with which it is brightened. 

In common telescopes the rays of light being 
difTeiently refrangible, all that could be done 
in this mode to give them perfection would be 
of very little advantage, because, that under 
whatever angle the object, or planet, appears 
to our sight, and whatever intensity of light it 



may liavo, the rays will never collect in the 
same part ; the longer the telescope the more 
interval it will have between the focus of the 
red and violet rays, and consequently the more 
confused the image of the object observed. 

Refracting telescopes, therefore, can be 
rendered perfect only by seeking for the means 
of correcting this eftect of the different refran- 
gibility, either by composing telescopes of dif- 
ferent densities, or by other particular means, 
which would be different according to different 
objects and circumstances. Suppose, for ex- 
ample, a short telescope, composed of two 
glasses, one convex and the other concave; it 
is certain that this telescope might be reduced 
to another whose two glasses would be plain 
on one side, and on the other bordering on 
spheres, whose rays would be shorter than that 
on the spheres on which the glasses of the first 
telescopes have been constructed. However, 
to avoid a great part of the effect of the dif- 
ferent refrangibility of the rays, the second te- 
lescope may be made with one single piece of 
massive glass, as I had it done with two pieces 
of white glass, one of two inches and a half 
in lengtli, and the other one inch and a 
half; but then the loss of transparency is a 
greater inconvenience than the different re-- 


232 uuffon's 

frangibilify wliicb it corrects, for these two 
small massive telescopes of glass are more 
obscure than a small common telescope of the 
same glass and dimensions ; they indeed give 
less iris, but are not better; for in massive 
glass the light, after having crossed this thick- 
Bess of glass, would no longer have a suffi- 
cient force to take in the image of the object 
to our eye. So to make telescopes 10 or 23 
feet long, I find nothing but water that has 
sufficient transparency to suffer the light to 
pass through this great thickness. By using, 
therefore, water to fill up the intervals be- 
tween the objective and the ocular glass, we 
should in part diminish the effect of the dif- 
ferent refrangibility, because water approaches 
nearer to glass than air, and if we could, by 
loading tlie water with different salts, give it 
the same rcfringent degree of power as glass, 
it is not to be doubted, that we should correct 
still more, by this means, the different refran- 
gibility of the rays. A transparent liquor 
should, therefore, be used, which would have 
nearly the same refrangible power as glass, for 
then it would be certain that the two glasses, 
with their liquor between them, would in 
part correct the effect of the diflerent refran- 
gibility of the rays, in the same mode as it 



is ^corrected in the small massive telescope 
which I speak of. 

According to the experiments of M. Bon- 
guer, the thicknes^s of aline of glass destroys ■§. 
of light, and consequently the diminution 
would be made in tlie following proportion : 

Thickness, .1, 2, 3, 4, 5, 6 lines 

lillttlUllUII, 7 -^Y "34 3" "24 oT 16 8 7 lT7S^49 

So that by the sum of these six terms we 
should find, that the light which passes Ihrough 
six lines of glass would lose tttIttj ^^^^ ^^5 
about If^ of its quantity. But it must be con- 
sidered, that M. Bouguer makes use of glasses 
which are but little transparent, since he has 
observed, that the thickness of a line of these 
glasses destroys |. of the light. By the experi- 
ments which I have made on different kinds of 
white glass, it has appeared to me that the 
light diminishes much less. These experi- 
ments are easy to be made, and are what all the 
world may repeat. 

In a dark chamber, whose walls were black- 
ened, and which I made use of for optical ex- 
periments, I had a candle lighted of five (a 
the pound ; the room was very large and the 
candle the only light in it; I then tried at what 
distance I could read by this light, and found 
that I read very easily at 24 feet four inches 
VOL. X. H h from 

234: buf^'on's 

from the candle. Afterwards, bavlng placed a 
piece of glass, about a line tliick, before it, at 
two inches distance, I found that I still read 
very plainly at 22 feet nine inches ; and sub- 
stituting to this glass another piece of two lines 
in thickness and of the same glass, I read at 
21 feet distance from the candle. Two 6f the 
same glasses joined one to the other, and 
placed before the candle diminished the light 
so much that I could only read at 17| feet dis- 
tance; and at length, with three glasses, I 
could only read at 15 feet. Now the lisrht of 
a candle diminishing as the square of the dis- 
tance augments, its diminution should have 
been in the following progression, if glasses 
had not been interposed : 2 — 2^•. 2 — 22| 
2__2J. 2— 17i. 2— 15, or 592^. 517^441. 
S06|. 225. Therefore the loss of the light, 
by the interposition of the glasses, is in the 
following progression: 84t4V' 151. 2h5^. 
367 i. 

From hence it may be concluded, that the 
thickness of a line of this glass diminishes only 
tVt o^ iJ^'^lj or about -f ; that two lines dimi- 
nishes m, not quite ^ and three glasses of 
two lines l^l, i. e. less than l. 

As this result is very different from that of 
M. Bouguer, and as I was cautious of sus- 
pect ing 


pecting the truth of his experiments, I re- 
peated mine uith common glass. For long 
telescopes water alone can be used ; and it is 
still to be feared that an inconveniency will 
subsist, from the opacity resulting from the 
quantity of liquor which fills the interval be- 
tween the two glasses. 

The longer the telescope the greater loss of 
light will ensue : so that it appears at first sight 
that this mode cannot be used, especially for 
'iong telescopes ; for following what M. Bou- 
guer says in his Optical Essay, on the gradation 
of liglit, nijie feet seven inches sea-water di- 
minishes the lisfht in a relation of 14 to 5 ; 
therefore these long telescopes, filled with wa- 
ter, cannot be used for observing the sun, and 
the stars would not have light enough to be 
perceived across a thickness of 2>) or SO feet of 
intermediate liquor. 

Nevertheless, if we consider, that by allow- 
ing]: onlv an inch, or an inch and a half, for 
the bore of an objective of SO (eei, we shall 
very distinctly perceive the planets in the com- 
mon telescopes of this length; we may sup- 
pose that by allowing a greater diameter to the 
o!)jective we should augment the quantity of 
light in the ratio of the square of this diameter, 
and, consequently, if an inch before suffices to 
see a star distinctly, in a common telescope, 


^^^ buppon's 

llir^e iiicbes bore would be sufficient to see it 
distinctly through a thickness of 10 feet water, 
and that with a glass of three inches diameter 
We should easilj see it through a thickness of 
20 feet water, and so on. It appears, therefore, 
that we might hope to meet with success in 
constructing a telescope on these principles ; 
for, bybicreasing the diameter of the objec- 
tive, we parlly regain the light lost by the de- 
feet of the transparency of the liquor. 

But ir appears to me certain that a telescope 
constructed on this mode would be very useful 
for observing the sun ; for supposing it even 
the leuglh of 100 feet, the light of that lumi- 
nary would not be too strong after having tra- 
versed this thickness of water, and we should 
be enabled to observe its surface easily, and at 
•leisure, without the need of making use of 
smoked glasses, or of receiving the image on 
pasteboard ; an ad vantage we cannot possibly 
derive from any other telescope. 

There would require only some tri /ling dif- 
ference in the construction of this solaAele- 
scope, if we wanted the whole face of the sun 
presented ; forsupposing it the length of 100 
feet, in this case, the ocular glass must be ten 
inches diameter; because the sun, taking up 
more than half a celesti;d degree, the image 
formed by t he object veto its focus at ICO feel, 



will at least have this length of ten inches; 
and (o unite it wholly, it will require an ocul 
lar glass of this breadth, to whicli only twenty 
inches of focus should be given to render it as 
strong as possible. It is necessary that the ob- 
jective, as well as the ocular glass, should be 
ten inches in diameter, in "order that the 
image of the sun, and the image of the bore 
of the telescope, be of an equal size with the 

If this telescope, which I propose, should 
only serve to observe tlie sun exactly, it would 
be of great service; for example, it would be 
very curious to be able to discover wheiher 
there beany luminous parts larger than others 
in (he sun ; if there be inequalities on its sur* 
face; and of what kind; ifthe spots float on its 
surface; or whether they be fixed tliere, &c. The 
brightness of its light prevents us from observ- 
ing this luminary with the naked eye, and the 
different refrangibility of its rays, renders its 
image confused when received in the focus of 
an objective glass, or on pasteboard, so that the 
surface of the sun is less known to us than that 
of any of the planets. The different r.fran- 
gibility o£ its rays would be but little corrected 
in this Jong telescope filled with water; but 
if the liquor could, by the addition of salts. 

2S8 buipfon's 

he rciiflcred as dense as glass, it woulct then ha 
ihe same as if there were onlj^ one glass to pass 
throngli; and it appears to me that infinitely 
jnore advantage would result from making 
use of these telescopes filled with water, than 
from the common telescopes with smoked 
glasses. ^ 

Whether that would or would not be the 
fact, this lioweveris certain, that to observe the 
sun, a telescope quite different is required from 
those that we make use of for the different 
planets ; and it is also certain, that a particular 
telescope is necessary for each planet, propor- 
tionate totheirintensity of light, that is, to the 
real quantity of light with which they appear 
to be enlightened. In all telescopes the ob- 
jectives arc required as large, and the ocular 
glass as strong, as possible, and, at the same 
time, the distance of the focus proportioned to 
the intensity of the light of each planet. To 
do this with the greatest advantage, it is requi- 
site to use only an objective glass so much tlie 
larger, and a focus so much the shorter, accordr 
ing to the light of the planet. Why has there 
not hitherto been made objectiveglassesof 243 
feet diameter ? The aberration oftherays, occa- 
sioned by the sphericity of the glasses, is the 
fcolc cause of the confusion, which is as the 


NATURAL HI ST our. :?39 

, square of the diameter of the tube; and it is 
for this reason that spherical glasses, with a 
small bore, are of no value when enlarged ; we 
have more iighJ, but less distinction and clear- 
ness. Nevertheless, broad spherical glasses are 
very good for night telescopes. The Englisk 
#lave constructed telescopes of this nature, and 
they make use of them very advantageously 
to see vessels at a great distance in dark nights 
But at present, that we know, in a great mea- 
sure, how to correct the effects of the different 
rcfrangibility of the rays, it seems, that we 
should make elliptical or hyperbolical glasses, 
which would not produce the alteration caused 
by sphericity, and which, consequently, would 
he three or four times broader than spherical 
glasses. There is only this mode of augment- 
ing to our sight the quantity of light sent io 
us from the planets, for we cannot put an ad- 
ditional light on them, as we do on objects 
which we observe with the microscope, but 
must at least employ to the greatest possible 
advantage, the quantity of light with which 
they are illumined, by receiving it on as great 
a surface as possible. This hyperbolical tele- 
scope, which would be composed only of one 
single large objective glass, and of an oculir 
one proportionate, would require matter of the 
greatest transparency; and we should unite 


sis BUFFO N'S 

by this means all the advantages possible, that 
is, those of the acromatic to that of the ellipti- 
cal or hyperbolical telescopes, and we should 
profit by all the quantity of light each planet 
reflecis to our sight. I may be deceived ; but 
what I propose appears to be sufficiently 
founded to recommend i!s execution to per- 
sons zealously attached to the advancement of 
the sciences. 

Employing myself thus on these reveries, 
some of which may one day be realized, and 
in which hope I publish them, I thought of 
(he Alexandrian mirror, spoken of by some an- 
cient authors, and by means of which vessels 
were seen at a great distance on the sea. The 
most positive passage which I have met with 
is the following. 

^' Alexandria .... in Pharo vero erat specu- 
*' lum e ferro sinico. Per quod a longe vide- 
*' bantur naves Graecorum advenientes ; sed 
*' paulo postquara Islamismusinvaluit, scilicet 
*' tempore califatus Walidfil: Abdi-I-melec, 
^' Christiani,fraude adhibita illud deleverunt. 
*' Abu-1-feda, &c. Dcscriptio iEgypti." 

Having dwelt for some time on this, I 
have thought, 1. That such a mirror was 
possible to be made. 2. That even without 
a mirror or telescope, we might by certain 



dispositions obtain the same effect, a^d see ves- 
sels from land, as far, perhaps, astlic curvature 
of tlie earth would permit. We have already 
observed that persons whose sight was very 
good, have perceived objects illumined by the 
sun at more than 3400 times their diameter, 
and at the same timt we hrwe remarked, that the 
intermediate light was of such great hurt to 
that of distant objects, that by night a lumi- 
minous object is perceived at ten, twenty, and 
perhaps a hundred times greater distance than 
during the day. We know that at the bottom 
of very deep pits, stars may be seen in the day- 
time* ; why therefore should we not see ves- 
sels illumined by the rays of the sun, by 
placing one's self at the end of a very long 
dark gallery, situated on the seashore, in such 
a manner as to receive no other than that of 
the distant sea, and the vessels which miglit be 
on it? This gallery would be only a hi ri- 
zoiital pit, which wotdd have the same effect 
with respect to ships as the vertical pit has 
with respect to the stars ; and it appears to 
me so simple, that I am astonished it has never 
before been thought of and tried. It seems to 
me, that by taking the time of the day for our 
VOL. X. I i observations 

* Aristotle is, I believe, the first that ever mentioned this 

242 BUFFO n's 

observations wlien the sun slioiild be behind 
the <]:allerv, we miffht sec them from the dark 
end of it ten times at least better than in the 
open light. Now a man on liorseback is easily 
distinoruished at a mile distance, when the 
rays of the sun shine on him, and by sup- 
pressing the intermediate liglit which sur- 
rounds us, and dPtrkening our sight, we should 
see him at least ten times farther ; that is to 
say, ten miles. Ships, therefore, being much 
larger, would be seen as far as the curvature of 
the earth would permit, without any other in*- 
stniment than the naked eye. 

But a concave mirror, of a great diameter, 
and of any focus, placed at the end of a long 
black tube, would Jiave nearly the same effect 
as our great objective glasses of the same dia- 
meter and form would have during the night, 
and it was probably one of these concave mir* 
Tors of polished steel that was established at 
the port of Alexandria*. If this steel mirror 
did really exist, we cannot refuse to the an- 
cients the glory of the first invention, for this 
mirror can only be effective by as much as the 


* From time immemorial the Chinese, and particularly 
the Japanese, have possessed the art of working in steel 
both in large and small bodies; and hence I have thought 
that the words eferro sinico in the preceding quotation should 
be understood as applying to polished steel. 


light reflected by its surface was collected by 
another concave mirror placed at its ft)cus, 
aiid in this consists the essence of the telescope 
and the merit of its construction. Neverthe- 
less this does not deprive the great Ncwtnn of 
any glory, who first renewed the almost-forgot- 
ten invention. As the rays of light are by their 
nature differently refrangible, he was inclined 
to think there were no means of correcting this 
effect, or, if he had perceived those means, he 
judged them so difhcult that he chose rather to 
turn his views another way, and produce, by 
means of the reflection of the rays, the great 
effects which he could not obtain by their re- 
fraction ; he, therefore, constructed his telc- 
•scQpe, the reflection of which is infinitely su- 
perior to those that were in common use. The 
best telescopes are always dark in comparison 
of the acromatic, and this obscurity does not 
proceed only from the defect of the polish, or 
the colour of the metal of mirrors, but from the 
nature even of light, the rays of which being 
differently refrangible are also differentlj^ re- 
flexible, although in much less unequal degrees. 
It still remains, therefore, to bring the tele- 
scope to perfection, and to find the manner of 
compensating ihia different reflexibility, as we 



hav€ discovered that of compensating the dif- 
ferent rcfrangibility. 

After all, I imagine that it will be well per- 
ceived tbata verj'goodday-gl»'^s may be made, 
withoui using either glasses or mirrors, and 
simply by suppressing the siirrounding light, 
by means of a tube 150 or ^50 feet long, and by 
placing ourselves in an obscure place. The 
brighter the day is, the greater will be the ef- 
fect. I am persuaded that we should be able 
io see at 15, and perhaps 20 miles distance. 
The only difference between this long tube, 
and the dark gallery, which I have spoken of, 
is, that the field, or the space seen, would be 
smaller,and precisely in the ratio of the square 
of the bore of the tube to that of the gallery. 




THE physical study of Ycgetables is one of 
those sciences which require a multiplicity of 
observations and experiments bej^ond the ca- 
pacity of one man, and must consequently be 
a work of time ; even the observations them- 
selves are seldom of much value till they have 
been repeatedly made, and compared in dif- 
ferent places and seasons, and by different per- 
gons of similar ideas. It was for this purpose 
that Buffon united with M. Dii Ilarael, to la- 
bour, in co:icert for the illustration of a num- 
ber of henomena, whicii appeared difficult to 
explain, in the vegetable kingdom, and from 
the knowledge of which may result an infinity 
of useful matters in the practice of agriculture. 

The frost is sometimes so intense during 
wit.tcr, that it destroys almost all vegetables, 
and the scarcity in the year 1709 was a melan- 
choly proof of its cruel effects. Seeds, and 
some kinds of trees, entirely perished, while 


^6 15ufpon's 

others, as olives, and almost all fruit-trees, sliar- 
^d a milder fate, shooting forth their leaves, 
tlreir roots not having been hurt; and manjr 
large trees, which were more vigorous, shot 
forth every branch in spring, and did not ap- 
pear to have suffered any material injury. We 
shall, nevertheless, remark on the real and ir- 
jcparablc damage this winter occasioned them. 

Frost, which can deprive us of the most ne- 
cessary articles of life, destroys many kinds of 
useful trees, and which scarcely ever leaves 
one insensible of its rigour, is certainly one of 
the most formidable misfortunes of human na- 
ture; we have therefore every reason to dread 
intense frosts, which might reduce us to the 
last extremities if their severities v/cre frequent ; 
but fortunately we can quote only two or tliree 
winters which have produced so great and ge- 
neral a calamity as that in 1709. 

The greatest spring frosts, although they 
damage the grain, and principally barley^ 
when it is but just eared, never occasion great 
scarcities. They do not affect the trunks or 
branches of (rees, but they totally destroy tlieir 
productions, deprive us of the harvest of the 
vines and orchards, and by the suppression of 
new buds cause a considerable damage to 



Although there are some examples of ^vinter 
frosts having reduced us to a scarcity of bread, 
and deprived us of vegetables,thcdamage which 
spring frosts occasion becomes still more im- 
portant, because tliey afflict us more frequcnt- 
Ij, and their effects are felt almost every year* 

To consider frost even very superficially, 
we must perceive that the effects produced by 
the sharp frosts of winter are very different 
from what are occasioned by those in spring, 
since the one attacks (he body and most solid 
parts of trees, whereas the other simj^y destroys 
4heir productions, and opposes their growth .; 
at the same time they act under quite different 
circumstances ; and it is not always the ground 
|n which the winter frosts produce the greatest; 
disorders, as that generally suffers most fron;i 
those in the spring frosts. 

It was from a great number of observations 
that we have been able to make this distinctioa 
on the effects of frost, and which we hope will 
not be simply curious, but prove of utility, 
and be profitabl(? to agriculture ; and should 
they not wholly enable us to escape from the 
evils occasioned by frost, they will afford us 
a means to guard against them. We shall, 
therefore, enter upon the detail, beginning 
•with that ^^hich regards the sharp frosts of 

wii.tcr : 

243 BUFFO n's 

"winter : of these, however, we cnnnot reason 
with so great a certainty as on those of spring, 
because, as we have already observed, we are 
seldom subjected to their tragical effects. 

Most trees during wi;iler being deprived of 
blossoms, fruits, and leaves, have generally 
their buds hardened so as to be capable of sup- 
porting very sharp frosts, unless the preceding 
summer was cool, in which case the buds not 
being arrived to that degree of maturity , which 
gardeners call crow/cs*, they are not in a state 
of resisting the moderate frosts of winter; but 
this seldom happens, the buds commonly rip- 
ening before winter, and the trees end are 
the rigour of that season without being damag- 
ed, unless excessive cold weather ensue, join- 
ed to the circumstances hereafter mentioned. 

We have, nevertheless, met with many trees 
in foresis with considerable def('cts,whichhave 
certainly been produced by the sharp frosts, 
and which will never be effaced. 

These defects are, 1st, chaps or chinks, 
which follow the direction of the fibres. 2. .1 
])ortion of dead wood included in the good ; 
and lastly, the double sap, which is an entire 
crown of imperfect wood. We must dwell 

a little 

* Ripened or filled vrith sap. 


a little on these defects to trace the causes 
whence they proceed. 

The sappy part of trees- is^ as is well known, 
a crown or circle of white or imperfect wood 
of a greater or less thickness, and which in 
almost all trees is easily distinguished from the 
sound wood, called the^ear^, by the difference 
of its colour and hardness ; it is found imme* 
diately under the bark, and surrounds the per- 
fect wood, which in sound trees is nearly of (he 
same colour, from the circumference to the 
centre. But in those we now speak of, the per- 
fect wood was separated by another circle of 
white wood, so that on cutting the trunks of 
them we saw alternately circles of sap and 
perfect wood, and afterwards a clump of the 
latter, which was more or less considerable, 
according to the different soils and situations ; 
in strong and forest earth it is more scarce tliaa 
in glades and light earth. 

By the mere inspection of these cinctures of 
white wood, which we in future shall terra 
false sap, we could perceive it to be of bad 
quality; nevertheless, to be certain of it, we 
had several planks sawed two feet in length, 
by nine to ten inches square, and having the 
like made from the true sap, we had both 
loaded in the middle, and those of the false sap 
VOL. X. K k alv/ays 

250 buffon'^s 

always brolie under a less \veigl)t than (li(E)se of 
the (rue, though (he strength of the true sap 
is very trivial in comparison with that of 
formed wood. 

We aficr wards took several pieces of these 
two kinds of sap, and weighed them both in 
th€ air anil water, by which we discovered that 
the specific weight of the natural sap was al- 
ways greater than that of the false. We then 
made a like experiment with tlie wood of the 
centre of the same trees, to compare it with 
that of the cincture which is found between 
these two saps, and we discovered that the dif- 
ference was nearly the same as is usual between 
the weight of the wood of the centre of all 
trees and that of the circumference ; thus all 
that is become perfect wood in these defective 
trees is found nearly in the common order. But 
it is not the same with respect to the false sap, 
for, as these experiments prove, it is weaker, 
bofter, and lighter tlian the true sap, although 
formed 20, nay 25 years befole, which we dis- 
covered to be the fact, by counting the annual 
cirdes, as well of the sap as of the wood which 
covered it; and this observation, which wc 
have repeated on a number of trees, Lncon- 
testibly proves that these defects had been 
caused by the hard frost of 1709, notwith- 



stand Lnsr til at the number of some of their coals 
was less than the years which had passed since 
that period ; and at which we must not be 
surprised, not only because we can never, by 
the number of li^i»eous coats, find the age of 
trees within three or four years, but also be- 
cause the first ligneous coats, formed after 
that frost, were so thin and confined, that we 
cannot very exactly distinguish them. 

It is also certain, that it was the portion of 
the trees that were in sap in the hard frost of 
i709, which instead of coming to perfection, 
and converting itself into wood, became more 
faulty. Besides, it is more natural to suppose, 
thatthe faulty part raustsufFer more from sharp 
frosts than sound wood : because it is not only 
at the external part of the tree, and therefore 
more exposed to the weather, but also because 
the fibres are more tender and delicate than the 
wood. All this at first appears to wear but 
little diflficulty, yet the objections related in 
the history of the Academy of Sciences, 1710, 
might be here adduced ; by these objections 
it appears that in 1709, the young trees en- 
dured the hard frost much better than old. 
But as these facts are certain, there mnst be 
some difference between the organic parts, the 
vessels, the fibres, &c. of the sappy part of 


55S buffon's 

the old trees and that of the young ; they per- 
haps will be more supple, so that a power 
which will be capable of causing the oue to 
break, will only dilate the other. 

But as these are conjectures with which the 
mind remains but little satisfied, we shall pass 
sligh'ly over them, and content ourselves with 
the particulars we have well observed. That 
this sappy part suffered greatly from the frost 
is an incontestible fact, but has it been en- 
tirely disorganized? This might happeii 
without the death of the tree ensuin^g, pro- 
vided the bark remained sound ; and even ve- 
getation might continue. Willows and limes 
frequently subsist only by their bark, and the 
same thing has beerv seen at the nursery of 
Roule in an orange tree. But we do not think 
that the false sap is dead, because it always 
apj>eared to lis in quite a different state from 
the sap found in trees, which had a portion of 
dead wood included in the sound ; besides, if 
it had been disorganized, as it extends over 
the whole cbcumference, it would have inter- 
rupted the lateral motion of the sap, and the 
wood of the centre, not being able to vegetate, 
would have ali / perished and altered, which 
was not the case, and which I could confirm by 
a number of experiments ; however, it is not 



easily conceivable iiow tliis sappy part of wood 
has been changed so far as not to become 
■wood, and that far from lacing dead, it was 
even in a state of supplying the ligneous coat^ 
wiUi sap, whicli are formed fro^n above in a 
state of perfection, and which may be com- 
pared to the wood of trees that have suffered 
no accident. This must nevertlieless have 
been done by the hard winter, which caused an 
incurable malady to this part of the tree; for if 
it were dead, as well as the bark which cloathed 
it, there can be no doubt that tlie tree would 
have entirely perished, which happened in 
.1709 to many trees whose bark was detached 
from them, and which by the remaininir sap in 
their trunk, shot forth their buds in spring, but 
died through weakness before autumn, for want 
of receiving sufficient nutriment to subsist on. 
We have met with some of these false sappy 
.part of' trees which are thicker on oiic side 
than the other, and which surprisingly agrees 
with the most general state of the sap. Wc 
have also seen others very thin, so that appa- 
rently there were only the outer coats injured. 
These were not all of the same colour, had not 
undergone an equal alteration,norwer;e equally 
affected, which agrees with what we have be- 
fore advanced. At length, we dug at the 


254 buffon's 

foot of some of these trees, to sec if tLe defect 
existed also in the roots, but we found them 
sound: therefore, it is probable that the earlh 
which covered them had repaired the injury 
done by the frost. 

Here then we see one of the most dreadful 
effects ofwinter frosts, which though locked up 
within the tree, is not less to be feared, since 
it renders the trees attacked by them almost 
useless; but besides this, it is very difficult to 
meet with trees totally exemjjt from these in- 
juries ; and indeed all those whose wood is not 
of a deeper colour at the centre, growing 
somewhat lighter towards the sap, may be sus- 
pected of having some defects, andouglit not 
to be made use of in any matter of consequence. 

By horizontally sawing the bottom of trees, 
wc sometimes perceive apiece of dead sap or 
dried bark, entirely covered by the live wood : 
this dead sap occupies nearly half of the cir- 
cumference in the parts of the trunk where it 
is found : it is sometimes browner than good 
wood, and at others almost white. From the 
depth also where this sap is found in the trunk, 
it appears to have been occasioned by the sharp 
frost in winter, by which a portion of the sap 
and bark perished, and wasaftcrwards covered 
hy the new wood ; for this sap is almost always 



found exposed to llie south, where the sun 
melting the ice, a humidity results, which 
again freezes soon after the sun disappears, and 
that forms a true ice, which is well known to 
cause a considerable prejudice to trees. This 
defect does not always appear throughout the 
whole length of the trunk, for we have seen 
many square pieces which seemed perfectly 
exempt from all defects, nor were the injuries 
of the frost discovered until they were slit into 
planks. It is, nevertheless easily to be con- 
ceived, how such a disorder, in their internal 
parts, must diminish their strength, and assist 
their perishing. 

In forests, or woods, we meet with trees 
which strong winter frosts have split accord- 
ing to the direction of their fibres; these are 
marked with a ridge formed by the cicatrice 
that covers the cracks, but which remain 
within the trees without uniting again, because 
a re-union is never formed in the ligneous 
fibres when they have been divided or broken ; 
nor can it be doubted, that the sap, which in- 
creases in volume when it freezes, as all liquors 
do, may produce many of these cracks. But 
we also suppose that there are some which are 
independent of the frost, and which have been 
occasioned by a too great abundance of sap. 


25S buffon's 

Be this as it may, the fact is, we have found 
defects of (his kind in all soils, and mall ex- 
Jmsitions, but most frequeiUly in wet ground 
and in nortliern and western expositions ; the 
letter may perhaps proceed in cases whert 
the cold is more intense, in such expositions ; 
and in the other, from the trees which are in 
marshy grounds, having the tissue of their lig- 
neous fibres weaker, and because their sap is 
more abundant and aqueous- tlmn in dry land;* 
which may be the cause that the effect of the 
rarefaction of liquors by the pores is more per-* 
ccptible, and more in a state of diminishing 
the ligneous fibres, as they bring less resist- 
ance thereto. 

This reasoning seems io be confirmed by 
anotlicr observation ; namely, that resinous 
trees, as the fir,aveseldom injured by the sharp 
frosts of winter, evidently from their sap bein^ 
more resinous : for we know that oils do not 
perfectly freeze, and that instead of augment- 
ing in volume, like water, in frosty weather, 
they diminish when they congeal. 

Dr. Hales says in his Vegetable Sialics, p. 16, 
that the plants which transpire the least, arc 
those which best resist the winter; because they 
have need of only a small quantity of nu- 
triment to preserve themselves. He says, 
likewise in the same part, that the plants, 



"Hbicli preserve their leaves during winter, are 
those ^vhich trcanspire the least ; nevertheless, 
we know that the orange tree, the myrtle, and 
still more the jessamine of Arabia, &c. are 
very sensible to frost, although these trees pre- 
serve their leaves during winter; we must, 
therefore, have recourse to another cause to 
explain why certain trees which do not shed- 
their leaves in winter, so well support the 
sharj^est frosts. 

We have sawed many trees which were at- 
tacked with this malady, and have almost al- 
ways found, under (he prominent cicatrice, a 
deposit of sap or rotten wood, and they are ea- 
sily distinguished from what are called in the 
forest terms, sinks or gutters, because the de- 
fects which proceed from an alteration of the 
ligneous fibres, which is internally produced, 
occasion no cicatrice to change the external 
form of the trees, whereas the cliinks produc- 
ed by frosts, w hich proceed from a cleft after- 
wards covered by a cicatrice, make a ridge or 
eminence in the form of a cord, which an- 
nounces the internal defect. 

The sharp winter frosts produce, without 
doubt, many oilier injuries to trees, and we 
Jiave remarked many defects, which we might 
attribute to them with great probability ; but, 
as we have not been able to verify the fact, we 
VOL. X. I, 1 ^]i^ll 

358 BUFFO n's 

shall pass on to the effects of the advantages and 
disadvantages of different expositions with rc^. 
spect to frost ; for this question is too interesting 
to agriculture not to attempt its elucidation, 
especially as various authors have supported an 
opposition of sentiment more capable of breed- 
ing doub:s than increasing our knowledge. 
Some have insisted that tlie frost is felt more 
strongly at the northern exposition, while 
others assert it is more sensible to the south or 
vrest, and all these opinions are founded on a 
single observation. We nevertheless perceive 
what has caused thisdiversity of opinion, and 
we are therefore enabled to reconcile them. 
But, before we relate the observations and ex- 
periments which have led us therelo, it is but 
just we should give a more exact idea or the 

It is not doubted that the grcalest cold pro- 
ceeds from the north, for that is in the shade 
of the sun, which alone, in sharp frosts, tem- 
pers the rigour of the cold ; besides, a situation 
to tlie north, is exposed to the north-east, and 
north-west winds, which are clearly the most 
intense, whether we judge from the effects 
which Lhose winds produce, or from the liquor 
of the thermometers, whose decision is much 
more certain. It may also be observed along 
the espaliers, that the earth is often frozen and 



hardened all the day towards the north, while 
it may be worked upon towards the south. 
Moreover when a strong frost succeeds in the 
night, it is evident, that it must be much colder 
in the part where it is already formed, than ia 
that where the earth is warmed by the sun ; this 
is also the reason why, even in hot countries, 
we find snow in tlie northern exposition, on 
the back of lofly mountains : besides, the li- 
quor of the thermometer is alwaj^s lower at 
the northern exposition, than in that of the 
south ; therefore, it is incontestible, that it is 
colder there, and freezes stronger. 

It is therefore certain, that all the accidents 
which depend solelj^on the power of the frost, 
will be found more frequently at the northern 
expo>iUon than elsewhere. But yet it is not al- 
ways the great power of the frost which injures 
trees, for there are particular accidents, which 
cause a moderatcfrost to do them more preju- 
dice than the mucii sharper, when they happen 
in favourable circumstances. Of this we have 
already given an example in speaking of that 
part of dead wood included in the good, which 
is producj^d by the hoar frost, and is found 
most frequently intlie expositions to ihe south ; 
and it is also to be observed, that great part of 
the disorders produced in the winter of i 709, 


^60 buffon's 

are to be attributed to a false thaw, w!iicli was 
followed by a frost still sharper than what had 
preceded ; but the observations which we 
have made on the eiTectsof spring frosts sup- 
ply us with many similar examples, which 
i neon test ibly prove it is not in the expositions 
where it freezes the strongest, that the frost 
commits the greatest injuries to vegetables, 
^ot to dwell upon assertions,we shall proccc.l 
to a detail of facts, which will render these 
general positions clear and apparent. 

In the winter 1734 we caused a coppice in 
my wood,, near Montbard in Burgundy, to be 
cut,which measured one hundred and fifty-four 
feet, situated in a dry place, on a Hat ground, 
surrounded on all sides widi cultivated land. 
In this wood we left many small square pieces 
without felling them, and in a manner that each 
equally faced east, west, noilh and south. Af- 
ter having well cleared the part that was cut, 
we observed carefully in spring the growth of 
the young buds ; the renewed tops on the 2jih 
of April, had sensibly shot out in the parts ex- 
posed to the soutli, and which consequently 
•were sheltered from the north by the tufted 
tops ; these were the first bucis that appeared, 
and were the most vigorous ; those exposed to 
the east appeared next ; then those of the 



west, and lastly those of the northern exposi- 
tion. On the 28th of April the ff^st \vas very 
sharp in the morning accompanied by anortli 
wind ; the .sky was clear, and the air very diy , 
and in whicb manner it continued for throe 
dajs. At the end of which I went to sec iu 
what slate the buds were about the cluinps, 
and found them absoiiitcly blacliei'.cd in all the 
parts exposed to the south and sheltered from 
the north wind, wherciis those wliich were ex- 
posed to the cold north wind, which still 
Wowed, were only slightly injured; and with 
resiDcctto the eastern and western expositions, 
they were that day nearly alike ifijured. 

The 14th, 15th, and 22d of May, it froze 
pretty sharply, accompanied by the north and 
north-west winds, and I then likewise observed 
that ali those sheltered from the wind were very 
much injured, but that all those which were 
exposed thereto had sufllrcd but very little. 
This experiment appeared decisive, and show* 
ed that although it froze most strong in p;irts 
exposed to the north wind, yet the frost in that 
-aitnationdid the least injury to vegetabics. 

This circumstance is certainly opposed to 
common prejudice ; but it is not less the fact, 
atid is even easy to be explained ; for this p.u- 
jK«M\ it h 'sufficient topay attcnlio;i tocirciun- 

g(j2 buffom's 

stances in wTiich frost acts, and we shall dis- 
cover that humidity is the principal cause of 
its effects, so thatall which occasions humidity 
renders, at the same time, the frost dangerous 
to vegetaljles, and all that dissipates humidity, 
evenlf it should be done by increasing the cold 
(for every thing 'hat dries diminishes the dis- 
asters ofa fro.t) acts towards their preservation. 
We have often remarked, that iu low places, 
where mists and fogs reign, frost is felt n»ore 
sharoly, and oftener than elsewhere. For in- 
stance, in autumn and spring we have seen de- 
licate plants frozen in a kitchen-garden, in a 
low situation, while the like plants were pre- 
served sound in another kitchen-garden situated 
on an eminence. So, likewise, in vallies and 
low forests the wood is never of a beautuul 
vein, nor of good quality, although the vallies 
are often by much the best soil . The coppice 
wood is never go.d in low places, although it 
shoots forth th6re later than upon high places, 
and which is occasioned by a freshness that is 
always concentered therein. When I walked 
H nioht in the wood I felt almost as much 
heat "on eminences as in the open plains, but 
in the vallies 1 experienced a sharp a,.d un- 
comfortable cold. Though the trees shoot out 
the latest in those parts, yet the shoots arc stil 



injured by <Iie frost, which spoiling the prin- 
cipalbudsobligesthe trees toshoot forth lateral 
branches, and thus prevents their ever becom- 
ing straight and handsome Irees fit for ser- 
vice. What we have just advanced must not 
be understood only of deep vallies, which 
are liable to those inconveniencies from nor- 
thern expositions, or those inclosed on the 
southern side in the form of an alley, in which 
it often freezes the whole year, but also of the 
smallest vallics, so that by a little custom we 
can discover the bad figure of the shoots from 
the inclination of the earth ; this Ipaiticularly 
observed on the 2Sth of April, 1734; on that 
day the buds of all the trees, from cnc year up 
to six or seven, were Aozcn in all the lower 
places; whereas in the high and uncovered 
places there were only the shoots near the earth 
which were so ; tlie earth was then very dry, 
and the humidity of the air did not appear 
to have greatly contributed to this injury. 
Neither vines, nor the trees of the plain, arc 
subject to frost, which might lead us to sup- 
pose they are less delicate than the oak ; but 
we think tliis must be atlributcd to the humi- 
dity, which is always greater in the woods than 
in the rest of the plains, for we have observed 
that oaks are often very much injured from 


^2G'i buffon's 

frosts in forests, wliile those \vl5ic1i are in (he 
plains arc not hurt in t];c least. 

JjiAYge timbers, even on ennnenccs, may 
cause the young' trees near them to be in the 
sanoc state as if at tlie bottom of a valley. We 
Lave also remarked, that the young wood near 
large trees is often more injured by (he frost 
than in parts remote from them, as in the 
midst of such woods, where a great number of 
branches are left, it is felt with more force than 
in ihoic which are o{3{'n. Now all these dis» 
orders are most considerable in such places, for 
as the wind and sun cannot di^sipate the tran- 
spiration of the earth and plants, there remains 
a considerable humidity, which causes a very 
great prejudice to plants. 

We have also remarked, that the frost is 
never more to be dreaded, with respect to the 
vine flowers, buds of trees, &c. than when it 
succeeds mists, or even rain, however slight, 
for they are all capable of enduring a very coUf 
siderable degree of cold without being damagr 
cd, when i( lias not rained for some time, ant} 
the earth is dry. 

Frosts likewise act more powerfully in places 

newly cultivated than in others, because the 

vapours, which conlinually risefrom the earth, 

, transpire more freely and abundantly from that 



which is newly cultivated. To this reason we 
mus(, however, subjoin the fact, that plants, 
newly set, shoot foith more vigorously than 
others, which renders them more sensible and 
liable (o (he effects of fro&t. So also in light 
and sandy soil the frost does more injury than 
in strong land, even though of equal dryness, 
because more exhalations escape from the first 
kind of earths than from the latter; and if a 
vine newly dunged is most subject to the frost, 
it arises from the humidity whicfi escapes from 
it. A furrow of vine which lies ah)ng a field 
of sainfoin, pea>, &c. is often all destroyed by 
the frost, while the rest of the vine is quite 
healthy, and this is undoubtedly, to be attri* 
buted to the transpiration of the sainfoin, or 
other plants, which bring a humidity on the 
shoots of the vine. In the vine also, the 
branches that are strong and cut are always 
less injured th:m the stock; especially when 
not attached tothe props, as they are then agi- 
tated by the wind which dries them. 

The same thing is remarked of limber, and 
I have seen in copses all the buds entirely de- 
stroyed by the frost, while the upper shoo s had 
not received the least damage ; indeed it always 
appeared that the frost did most injury nearest 
to the earth, commonly within one or two feet, 
VOL. X. Mm insomuch 

S66 BUFFO n's 

insomiicli that it must be very violent to de- 
stroy the buds higher than four. 

All these observations, which may be re- 
garded as very constant, agree to prove that in 
general it is not the sharpest frosts which do 
the greatest injury to plants, but that they are 
affected in proportion as they are loaded with 
humidity, which perfectly explains why the 
frost causes so many disorders in the southern 
exposition, although it should be less cold than 
that of the north, and likewise why the frost 
causes more injury to the northern exposition, 
when after a rain proceeding from a westerly 
wind the wind veers to the north towards sun- 
set, as often happens in spring, or when, by 
an easterly wind, a cold moist air arises before 
sun-rise, which, however, is not so common. 

There are likewise circumstances where the 
frostdoes most injury to the eastern exposition ; 
but as we have many observations on that sub- 
ject, we shall first relate those which we made 
in the spring frost in 1736, which occasioned 
so much damage. It having been very dry 
previously, it froze for a long time before it in- 
jured the vines ; but it was not so in the forests, 
apparently because they contained more hu- 
midity. In Burgundy it was the same as in 
the forest of Orleans, the underwood was in- 


jurcd very earij. At last the frost increased 
so greatly that all the vines were destroyed, 
notwithstanding the dryness still continued ; 
but instead of this frost doing much damage 
under thesheltcr of the wind, those parts which 
were sheltered were the only ones preserved, 
insomuch, that in many closes surrounded by 
walls the stocks along the southern exposition 
were very green, while all the rest remained 
dry ; and in two quarters the vines were saved, 
tlie one by being sheltered from the north by 
a nursery of ash-trees, and the other because 
the vineyard was stocked with a number of 
fruil -trees. 

But this effect is very rare, and this hap- 
pened only because the season had been dry, 
and because the vines had resisted the wea-- 
ther till the plants had became so strong, from 
the time of the year, that the frost could not 
injure them, independently of the external hu- 
midity and other particular circumstances. 

But there are other causes to be assigned 
v/hy frost produces injury more frequently to 
the east than to the west, and which are drawn 
from the following observations : 

A sharp frost causes no prejudice to plants 
when it goes off before the sun comes upon 
them : let it freeze at night, if the morning be 


268 bupfon's 

cloudy, or a slight rain fall, or, in a word, if 
by any cause whatever the ice melt gently, 
and independently of (he action of the sun, it 
seldom does Any injury ; and we have very 
often saved very delicate plants, which had by 
chance remained exposed to ihe frosts, by re- 
turning them into the green-house before sun- 
rise, or by simply covering them before the sun 
' had shone upon them. 

One time in particular a very sharp frost 
happened in autumn while our orange-lrecs 
were out of the green-house, and as it rained 
part of the night they were all covered with 
icicles: but this accident was prevented from 
doing any injury by covering them with cloths 
before the sun rose, so that there was only the 
young fruit and the most tender shoots injured, 
and we are persuaded they would all have 
been saved if the covering had been thicker. 

Another time oxxr geraniums ^ and many other 
plants which cannot bear the frost, were out, 
when suddenly the wind, which was south- 
west, veered to the north, and became so cold 
that the rain, which fell abundantly, was 
frozen, and in almost a moment all that were 
exposed to the air were covered with ice ; 
we thought, therefore, that all our plants were 
irrecoverably destroyed ; nevertheless we had 



them carried to the furthermost part of the 
green-house, shut up the windows, and by 
that means they sustained but little damage. 

This kintl of precaution is always observed 
with regard to animals ; whcnlhey are stricken 
with cold, or have a limb frozen, great care 
is taken not to expose them hastily to heat, but 
they are rubbed with snow, dipped in water, 
or burned in dung; in one word, the greates^t 
attention is paid that they shall gradually be 
brought to warmth. It is almost certain, with 
respect to fruit which may be frozen, that if 
thawed with precipitation it invariably j3e- 
rishes, whereas it suffers but little if thawed 

In order to explain how the sun produces 
so manj^ disorders in frozen plants, some have 
imagined that the ice, by melting, is reduced 
into small spherical drops of water, which 
form so many small burning mirrors when the 
sun shines upon them. But however small 
the form of a mirror may be, it can only pro- 
duce heat at a distance, and can have no effect 
on a body it touches ; besides, the side of the 
drop of water which is on the leaf of a plant 
is flat, wliich removes its focus to a greater 
distance. In short, if these drops of water 
could produce this effect why should not the 


§70 buffon's 

dew-drops, which are also splierical, produce 
the same ? Perhaps, it may he tliought that 
the most spirituous and volatile parts of the sap 
meitini^ the first, they evaporate before the 
rest are in a state of moving in the vessels of 
the plant, which might decompose the sap. 

But in general it may be said, that the frost 
increasing the volume of fluids, dilates the ves- 
sels of plants, and that the thaw cannot be 
performed without the parts which compose 
the frozen fluid enter into motion. This 
change may be made with suflicicnt gentleness 
not to break the most delicate vessels of plants, 
which will by degrees return to their natural 
tone, and then the plants will not suffer any 
injury; but, if it be done with precipitation, 
these vessels will not be able to resume their na- 
tural tone so soon after having suflbred a vio- 
lent extension, the liquors will evaporate and 
the plant remain dry. 

Although we might conclude wilh these 
conjectures, wi;h which I am not myself per- 
fectly satisfied, yet the following data are irre- 
vocably constant. 

1. That it seldom happens with regard to 
fruit, ei'.her in spring or winter, that the plants 
are injured simply by the force of the frost and 
independently of any particular circumstances, 



and when it does, it is at the northern exposi- 
tion that plants meet with the greatest injur^^. 
2. In frosty weather, which lasts several days, 
the heat of the sun melts the ice in some places 
for a few liours ; for it often fieezcs again be- 
fore sun-set, whicli forms an ice very preju- 
dicial to plants, and it is observable that the 
southern exposition is more subject to this in- 
convenience than all the rest. 

3. It has been observed, that spring frosts 
principally disorder those plants where there is 
humidity, the soils which transpire much, the 
bottoms of vallies, and in general all phices 
which cannot be dried by the wind and sua 
are the most injured. 

• In short, if, in spring, the sun which shines 
on frozen plants occasion a more considerable 
damage to them, it is clear that it will be the 
eastern exposition, and those next the south 
which will suffer most. 

But it may be said, if this be the case, we 
must no longer plant tothe souihern expositijn 
en a-dos (which are slopes, or borders of earth, 
thrown up in kitchen gardens or along espa- 
liers) gilliflowcrs, cabbages, winter lettuces, 
green peas, and such othc'r delicate plants as 
we would have stand the winter, and preserve 
for an early crop in spring : and that it is t'3 


272 supfon's 

the northern exposition alone that we must in 
future plant peach and olher delicate trees. 
It is proper to destroy these objections, and 
shew that Ihey are false consequences of what 
we have advanced. 

Different objects are proposed when we set 
plants to pass through the winter in shelters 
exposed to the south, and sometimes it is to 
expedite vegetation: it is, for example, with 
this intention, that along espaliers we plant 
ranges of lettuces, which for that reason are 
termed winter-hiiuces ; these will tolerably 
well resist the frost in whatever part we plant 
them, but are always most forward in this ex-» 
position ; at other times, it is to preserve them 
from the rigour of this season, with an inten- 
tion of replanting them early in the spring. 
This practice is also followed in winter cab- 
bages, which are sown in this season along an 
espalier border. These kind of cabbages, 
like brocoli, are tender and cannot endure the 
frost, and would often perish in these shelters, 
if care were not taken to cover them durin<r 
the sharp frosts with straw or dung supported 
on frames. 

To forward the vegetation of some plants 
which will not bear the frost, as green peas, &c. 
it is usual for that purpose to plant them on 



borders exposed to Ihe south, besides ^vhich, 
they are defended from sharp frosts \vhc:i the 
weather requires it. 

It is well known, without being compelletl 
to dwell any longer on this point, that the 
southern exposition is more proper than all 
the rest to accelerate vegetation, and we have 
shewn that this is also what is princip:\lly 
proposed when some plants are set in that ex- 
position to pass through the w inter, since, in 
addition, we are aUo obliged to make use of 
coverings to guard those plants which are very 
delicate from the frost. But we must add, 
tliat if there be some circumstances wherein 
the frost causes more disorders to the southern 
than toother expositions, there arcaLo many 
cases which are favourable to this exposition : 
for exaniple, in winter, when there is any 
t!)ing to tear from tiic ice. it freqtiently 
happens that the heat of ilie sun, increased by 
the reflection of the wall, has sufncienl force to 
dissipate all the li uni id ity, and tlien tl:e jlants 
are almost perfectly scciue against the cold. 
Besides, dry frosts oncn happen, Nvhich uncea- 
singly act tovvards the north, and wliich are 
{scarcely ever felt towards the south . In spring, 
likewise, we perceive that after a raiii which 
proceeds from the sonth-wcst, or south-east, if 
the wind chang;* to the r.orti), t'lc southerji 
vol.. X. rs n o?-. nailer 

274 buffon's 

espalier being under the shelter of the wind^ 
will suffer more than the rest ; but these cases 
are very rare, and most often it is after rains, 
which come from the north-east or north-west 
that the wind changes to the north, and then 
the southern espalier having been under shelter 
from the rain by the wall, the plants there wiU 
have less to suffer than (he rest, not only be- 
cause it will have received lets rain, but also 
because there is always less cold here, than in 
other expositions. It is likewise to be ob- 
served that as the sun dries much earth along 
the espaliers which are to the soutli, the earth 
transpires there less than elsewhere. 

It is well known that what we have just ad- 
vanced must be considered as applying also 
to peach and apricot trees, which it is custo- 
mary to put in this exposition and in that of 
the east. AVe shall only add, that it is not 
unusual to see peach trees frozen in the east 
and southern expositions, while those are not 
so which stand in the west or north ; but not- 
withstanding this we can never rely on having 
many, nor good peaches in this last exposition, 
for great quantities of blossoms fall oft' entirely 
without setting; others, after having set fall 
from the trees, and those Avhich remain with 
difficulty arrive to maturity. I have an 
espalier of peach-trees in a western exposition, 

a little 


a little declining to the north, which scarcely 
^vcr produce any fruit, although the trees are 
liandsomer than those to the southern and 
northern. We cannot, therefore, avoid the 
inconveniences of the frost with respect to the. 
southern exposition without feeling others that 
are worse. 

All delicate trees, as fig. laurel, &c. must be 
set to the south, and great care taken to cover 
them ; it is only requisite to remark that dry 
dung is preferable for this purpose to straw, 
because the latter not only does not so exactly 
.cover them, but also from its always retaining 
some grain which attracts moles and rats, who 
sometimes eat the bark of trees to quench their 
tliirst in frosty weather, when they can meet 
with no water to drink, nor herb to feed upon ; 
and however singular this may appear, it is a 
circumstance which lias happened to us several 
times ; but Avhen dung is made use of it must 
be dry, without which it will heat and make 
the young branches grow mouldy. 

All these precautions are, nevertheless, very 
inferior to the espaliers in niches, as in that 
manner plants are sheltered from all winds, 
except the south, which cannot hurt them ; 
the sun, which warms these places during the 
&i\yy prevents the cold from being so violent 
during the iiiglit ; and over tistse defended 



places v/e mny put a slight coveriiii^ wiili great 
facilKy, wliicli ^vill liolcl the plants there in a 
state of dryness, it) finitely proper to prevent 
all ihe accidents which (lie spring frosts and 
ice rnig!)t produce ; and most plants will not 
Rnfirr from being deprived of their external 
Iiuriiidity, because they scarcely transpire in 
the winter, or in the beginning of spring, so 
that the humidity of the air is sufficient for 
their supply. 

But since tlie dew renders plants so suscep- 
tible of (he spring frost, might we not liope, 
fhat from the researclies of Messrs. Musschen- 
brorck and Fay, some inferences may be de- 
duced wirlch may turn to the advantage of 
agriculture ? for since there are some bodies 
whicli seem to attract dew, while others evi- 
dently repel if, if we could paint, plaster, or 
wa-h the walls witli some matter which would 
have tlie latter effect, it is certain we should 
have room to expect a more fortunate success 
tlia'i from the juecaution taken to j lace a 
plank in form of a roof over the espaliers, 
which cannot prevent the abundancc'of dew 
from resting on trees, since Fay has proved 
(hat it very ofien does not fall perpendicularly 
like rain, but floats in the air, and attaches 
iiselfto those bodies it encounters ; so that fre- 
cjuendy as much dew is amassed under a roof 



as m places entirely open. It would be easy 
ibr us to recapitulate all our observations, and 
continue to deduce useful consequences, but 
•what we have said must be sufficient to shew 
the necessity of rooting up all trees which 
prevent the wind from dissipating mists. 

Since b}^ cultivating the earth we cause more 
exhalations to issue, great attention should be 
paid not to cultivate them in critical times. 

We must expressly declare against sowing 
kitchen-plants on vinc-furrow's, as by their 
transpiration they hurt the vine. 

Props sliould be put to the vines as late as 
possible. The hedges, which border thera on 
the north side, should be kept lower than the 
rest. It is preferable to improve vines with 
mould rather than dung. And in choosing a 
soil we should avoid those whicli are in bot- 
toms and grounds which transpire much. 

A part of these precautions may be also 
usefully employed for fruit-trees; with res- 
pect, for example, to plants which gardeners 
are forward to put at the feet of their bushes 
and along their espaliers. 

If there are some parts high and others low 
in a garden, Ave should pny attention to sow- 
spring and delicate plants on elevated parts, at 
least if we do not design to cover them witii 
glasses^ &c. but in cases where humidily can- 

278 bufI'On's 

not hurt them it might be often advantageous to 
choose low places, where they might be shcU 
tered from tlie north and north-west winds. 

Wc may also profit from what has been said 
1o the advantage of forests, for if we mean to 
make a reserve of any of the trees, it should 
never be in parls wliere the frost is severe ; and 
in planting we should pay attention to put in 
vallies those trees which can endure the frost 
better than the oak. 

When any coui^iderable fall of timber is 
made wc should make tljeni in roads, beginning 
always on the north side, in order that the 
v,-ind, which generally blows in frosty weather, 
may dissipate that humidity which is so pre- 
judicial to the underwood. 

There might be also many other useful con* 
sequences drawn from our ol>servati{)ns ; but 
\ye shall content ourselves with having briefly 
adverted to some, because the ingenious man 
may supply what we have omitted by paying a 
little attention to the observations we have 
mentioned. We are well convinced there are 
a great number of further experiments to be 
made on this matter ; and perhaps even ihose 
•which we have related will engage Fome per-^ 
€ons to work on the same subject, and from 
our hints general and useful advantages may 
be derived. 



MAN newly created, and even the igno- 
rant man at this day beholds the extent and 
nature of the universe only by the simple organ 
of light : to him the earth is but a solid body, 
whose volume is unbounded, and whose ex- 
tent is without limits, of which he can only 
survey small superficial spaces : while the sun 
and planets seem to be luminous points, of 
which the sun and moon appear to be the only 
objects worthy regard in the immensity of th^ 
heavens. To this false idea on the extent of 
^^ature and the proportions of the universe is 
joined the still more disproportionate sentiment 
of superiority. Man, by comparing himself 
with other terrestrial beings, feels that lie ranks 
the first, and hence he presumes that all was 
made for him ; that the earth was created only 
to serve for his habitation, and the heavens for 
a spectacle; and in short the whole universe 
ought to yield to his necessities, and even his 
pleasures. But in proportion as he makes use 
of that divine light, which alonie ennobles hi* 



being ; in proportion as he obtains instruction^ 
he is forced to abate his pretensions ; he finds 
himself lessened in proportion as the universe 
increases in his ideas, and it becomes demon- 
strable to him, that the earth, which forms all 
his domain, and on which unfortunately he 
cannot subsist without trouble and sorrow, is as 
small with respect to the universe, as he is with 
respect to the Creator. In short, from study 
and application, he finds that there does not 
remain a possible doubt, that this earth, large 
and extensive as it may seem to him, is but a 
moderate sized planet, a small mass of matter, 
which, with others, has a regular course round 
the sun : for as it appears our globe is at the 
distance of at least 33 millions of leagues, and 
the planet Saturn at Si3 millions, the natural 
conclusion is, that the extent of the sun's em- 
pire is a sphere, whose diameter is 627 millions 
of leagues, and that the earth, relative to this 
space, is not more than a grain of sand to the 
volume of the globe. 

However, the planet Saturn, altliough the 
furtliest from the sun, is not by uny means near 
the confines of his empire: his limits extend 
m'lch further, since comets ])ass over spaces 
beyond that distance, as n)ay be estimated by 
the time of their revolutions : a comet which 



like that ofthe jear 1680 revolves round the 
i^im in 575 years must be 15 times more remote 
from him than Saturn ; for the great axis of 
its orbit is 138 times greater than the distance 
from the earth to the sun. Hence we must still 
augment the extent of the solar power 15 times 
the distance from the sun to Saturn, so thatall 
the space in which the planets are included is 
only a small province of his domain, whose 
bounds should be placed at least 138 times his 
distance from the earth. 

What immensity of space ! What quantity of 
matter ! For independently ofthe planets, there 
is a probability ofthe existence of 400 or 500 
comets, perhaps larger than the earth, which 
run over the different regions of this vast 
sphere of which the terrestrial globe only con- 
stituting a part, a unity on 191, 201, 612, 9S5y 
514, 272, 000, a quantity represented by num- 
bers, which imagination cannot attain or com-* 

Nevertheless, this enormous extent, this vast 
sphere, is yet only a very small space in the im- 
mensity of the heavens; each fixed star is a sun, 
a center of a sphere equally as extensive ; and 
as we reckon more than 2O0O of these fixed 
stars perceived by the naked eye^and as with 
telescopes we can discover so much the greater 
number as these instruments are more powerful ; 
voB. X. O a the 

282 buffon's 

the extent of tlic universe appears lobe \vit1i» 
out bounds and the solar system forms only a 
province of the universal empire of the Crea- 
tor ; an infinite empire like himself. 

Sirius, the most brilliant fixed star^and which 
for that reason may be regarded as the nearest 
sun to our's, affords to our sight only a second 
of annual parrallax on the whole diameter of the 
earth's orbit, and is therefore at the distance of 
6, 771, 770, millions of leagues distant from 
us, that is, 6, 767, 216 millions of leagues 
from the limits of the solar system, such as we 
have assigned it after the depth to which the 
comets immerse. Supposing then, there is an 
equal space from Sirius to that which belong* 
to our sun , we shall perceive that we must ex- 
tend the limits of our solar system 742 times 
more than it is at present, as for as the aphe- 
lion of the comet, ivhose enormous distance 
from the sun is nevertheless only a unit on 742 
of the total diameter of the solar system. 


Distance from the earth to the Sun - - 33,000,000 

Distance from Saturn to the Sun - - 3l3,OOO,CC0i 

Distance from the aphehon of the Comet to 

the Sun - - - 4,554,000,000 

Distance from Sirius to the Sun - 6,771,770,000,000 

Distance of Sirius to the point of the aphe- 
lion of the Comet, supposing that in as- 
cending; from the sun the comet point- 
ed directly towards Sirius (a supposition 



which diminishes the distance as much as 

possible) - - 6,767^16,030,000 

Oue half the distance from Sirius to the 

Sun, or the depth of the solar and sircin 

system - - 3,385,S85,0(X),OCO 

Extent beyond the Hmits of the comet's 

aphelion - - 3,331,331,000,000 

Which being divided by the distance of the 

comet's aphelion, gives about - 742§ 

We can form another idea of our immense 
distance from Sirius, by recollecting that the 
sun's disk formstooursisrht an'ancrle of 32 mi- 
nutes, wliereas that of Sirius forms only that of 
a second ; and Sirius being- a sun like ours, 
■wliich we shall suppose of equal magnitude, 
since there is no reason to conceive it larger or 
smaller, it would appear to lis as large as the 
sun, if it were but a like dislance. Taking 
therefore two numbers proportional to the 
square of 32 minutes, and to the square of a 
second, we shall have 3,686,4000 for the dis- 
tance of the earth to Sirius, and one for its 
dibtuncc to the sun ; and as this unit is equal 
to c3 millions of leagues, we see how many 
millions of leagues Sirius is distant from us, 
since we must multiply these 33 millions by 
3,686,400 ; and if we divide the space between 
these two reighbouring suns, althougli at so 
great a distance, we shall sec that the comets 
might be removed to a distance 1.800,000 times 


2iS4 BUFFO n's 

ffrcaler Mian (hat of the earth to (he sun withr 
out quittinfi^ the limits of (he solar universe, 
and without bcingsulrjectcd to other laws than 
that of our sun, and lieuce it may be concluded 
that the solar system for its dianie(er has an 
extent, which, although prodigious, never- 
theless, forms on! J a very small portion of the 
licavcns ; and we must infer a truth therefrom 
but little known, namely, that from the sun, 
the earlh and all the other planets, the sky 
must appear the same. 

When in a serene and clear night we con- 
template all those stars nith which the celestial 
vault is illuminated, it might be imagined that 
by being conveyed into another planet more 
remote from the sun, we should see these glitter- 
ing stars larger, and emitting a brighter light, 
since we siiould be so much nearer to them. 
Nevertheless, the calculation we have just 
made demonstrates that if we were placed in 
Saturn, which is 300 millions of leagues nearer 
Sirius, it would appear only an ]9i,021st 
part bigger, an augmentation absolutely insen- 
sible ; from which it must be concluded, that 
the heaven, with respect to all the planets, lias 
the same aspect as it has lo the ear(h. There- 
fore if even there should exist comets whose 
periods of revolution might be double, or 



4veble the period of 575 yrars, tlie longest 
known to us ; if even tlic comets in coiisct* 
qiieiice thereof, immerse at a depth ten times 
greater, there would still he a space 74 or 75 
times deeper j to reach the iast coniincs,as well 
of the solar system, as of the sirian ; so that 
by allowing" Sirius as much magnitude as our 
sun has, and supposing in !iis system as muny 
or more cometary bodies than tiMere are comets 
existing in the solar, Sirius will govern them 
as the sun governs his, and tJiere will renuiin 
an immense interval between the coniines of 
the two enipires; an interval which appears 
to be no more than a desart in the vast space, 
and which must give a suspicion t!)at cometa- 
ry bodies do exist, whose periods are longcT,and 
which are to a muchgreaterdistance than we. 
can determine by our actual knowledge. Sirius 
may also be a sun much l.uger and more 
powerful than ours ; and if ihvd is tlie case, it 
must throw the borders of his doinain so much 
the further back by approaching them to us, 
and at the same time retrench the circumfe- 
rence of the sun. 

I cannot avoid presuming, that in tin's great 
number of fixed stiirs, which are all so many 
suns, there are some greater and others smaller 
than ours; others more or less luminous, some 


2SG buffon's 

nearer, wliich are represented to us bj those 
stars called by astronomers, stars of Ute first 
magm'ltide, and many oliiers more remote, 
which for that reason appear Jo us smaller. 
The stars called iuhulous seem to "want light 
and fire, a:id io be only half lighted ; those 
which appear and disappear alternately are, 
perhaps, of a form flattened by ihc violence of 
the centrifugal force in their motion of rotation, 
and are perceiveableonly when they are in the 
full, disappearing when they are sideways. In 
this grand order of things, and in the nature of 
the stars, there arc the same varieties, and ihe 
same differences, in number, size, space, ma* 
tion, form, and duration; the same relation, 
the same degrees, and the same coimection, as 
are found in all the other orders of the creation. 
Each of the suns being endowed like ours, 
and like all matter, with an attractive power, 
which extends to an indefinite distance, and 
decreases, as the space increases, analogy leads 
us to imagine that within each of their spheres 
there exists a great number of opaque bodies, 
planelSjOr comets, which circulate round them, 
but which bcinof much smaller than the suns 
which serve them for heat, they are beyond 
the reach of our si"ht. 



It might be imagined that comets pass from 
one system to the other, and that if they hap- 
pened to approach the confines of the two em- 
pires they would be attracted by the prepon^ 
derating power, and forced to obey tlic laws 
of a new master. Biii, by the immensity of 
space which is beyond (he aphelion of our co- 
mets, it appears that the Sovereign Ruler has 
separated each system by immense dcsarts, a 
thousand and a thousand times larger than all 
the extent of known spaces. These desarts, 
which numbers cannot fathom the depth of, 
are external and invincible barriers, that ail 
the powers of created nature cannot surmount. 
To form a communication from one system to 
the other, and for the subjects of one to pass 
into the other, it would be requisite that the 
centre was not immoveable, for the sun, the 
head of the system, changing place, would 
draw with it in its course all the bodies which 
depend thereon, and hence might approach 
and invade another demesne. If its rout were 
directed towards a weaker star, it would com- 
mence by carrying off the subjects of its most 
distant provinces, afterwards those more inte- 
rior, and would oblige them all to increase its 
train by revolving round it ; and its neiglibour 
thus deprived of its subjects, no longer liaving 
planets nor comets, would lose both its h'ght 


^S8 liUFFON's 

and fire, which their motion alone can excite* 
and support; hence this detached star, being 
no longer maintained in its place by the equili- 
brium of its farces, would be obliged to change 
nutrition, by changing nature, and becoming 
an obscure body, would, like the rest, obey the 
power of the conqueror, whose fire would in-* 
crease in proportion to the number of its con- 

For what can be said on the nature of the 
junbut that it is a body of prodigious volume^ 
an enormous mass of matter penetrated by 
fire, which appears to subsist without aliment, 
and which resembles a metal or a solid body in 
incandescence ? And from whence can this con- 
stant state of incandescence, this continually re- 
newed production of fire proceed, whose con- 
sumption does not appear to be supported by 
any aliment, and whose deperdition is at least 
insensible, although constant for such a great 
number of years ? Is there, or can there be, 
any other cause of the production of this per- 
manent fire, but the rapid motion from the 
strong pressure of all bodies, wliich revolve 
round this common heat, and wliich heats and 
sets fire to it, like a wheel r.ipidly turned round 
its axis ? The pressure, wliich tliey exercise by 
virtue of iheir weight is equivalent to the fric-* 
tioii, and even more powerful, because this^ 



pressure is a penetrating power, which not only 
rubs the external surface but all the internal 
parts of the mass : the rapidity of their raotioa 
is so great tliat the friction acquires a force al- 
most infinite, and consequently sets the whole 
mass of tlie axis in a state of incandescence, of 
light, of lieat, and of fire, which hence has no 
need of aliment to be supported, and which, 
in spite of the deperdition each day made by 
the emission of light, may remain for ever 
without any sensible alteration, other suns ren- 
dering as much light to ours as it sends to them, 
and no part of the smallest atom of fire, or any 
otlier matter, being lost in a system wliere all is 

If from this sketch of the great table of the 
heavens, and in wliich I have only attempted to 
represent to myself the proportion of the spaces, 
and that of the motion of bodies which travel 
over them ; if from this point of view, to which 
I only raised myself to see how greatly nature 
must be multiplied in the difierent regions of 
the universe, we d<?scend to that proportion of 
space which we are better acquainted with, 
and in which the sun exercises its power, we 
shall discover, that although it governs all 
bodies therein, it, nevertheless, has not the 
yoL. X. P p power 

I'tower of vivifying thera, nor even that of sup-^ 
porting life and vegetation. 

Mercury, which is the nearest to the sun, 
nevertheless receives only a heat 400 times* 
stronger than that of the earth, and this heat, 
so far from being burning, as it has alwaj's 
been supposed, v. ould not be strong enough of 
itself to support animated nature, for the actual 
heat of the sun on the earth being only -^ part 
of the heat of the terrestrial globe, that of the 
sun on Mercury consequently is only \ part of 
the actual heat of the earth. Now if | parts 
were subtracted from the heat which is at pre* 
sennt the temperature of the earth, it is certain 
animated nature would be checked, if not en^ 
tirely extinguished. Since the sun alone can- 
not maintain organised nature in the nearest 
planet, how much more aid must it require to 
animate those at a greater distance ? To Venus 
it only sends a heat -^ times stronger than that 
it sends to the earth, which instead of being 
strong enough to support animated nature, 
would no; certainly suffice to maintain the li- 
quidity of water, nor perhaps even the fluidity 
of air, since our actual temperature would be 
refrigerated to ^^ which is very near the term 
■^j we have given as tha external limit of the 



siiscbtest heat, relative to living' nature. And 
with respect to Mcvrs, Jupiter, Saturn, and all 
their satellites, the quantity of hoot which the 
sun sends to them, in comparison with that 
-which is necessary for the support of nature, 
which may be looked upon as of little cllect^ 
<especially in the two larger planets, which, ne- 
vertheless, appear to be the essenlialobjects of 
the solar system,. 

All the planets, tlierefore, hav^ always been 
volumes (as large as useless) of matter more 
than dead, profoundly frozen, and consequent-. 
>ly places uninhabited and 41 n in habit able fox 
ever, if they do not include within themselves 
treasures of heat much superior to what they 
receive from the sun. The heat wiiich our 
globe possesses of itself, and which is 50 times 
greater than that which comes to it from the 
sun, is, in fact, the treasure of nature, the true 
fund which animates us as well as every being : 
it is this internal heat of the earth which causes 
all things to germinate and to develope; it is 
that which constitutes the element of fire, 
properly called an element, which alone gives 
motion to other elements, and which if it was 
reduced to -^ could not conquer -their rcsist- 
ftnce,but would itself fall into an inertia. Now 
4hls element, this sole active power, whicli 


292 buffon's 

may render the air fluid, the water liquid, and 
the earth penetrable, might it not have been 
given to the terrestrial globe alone ? Does ana- 
^^gy permit us to doubt that the other planets 
do not likewise contain a quantity of heat, 
which belongs to them alone, and which must 
render them capable of receiving and support- 
ing living nature ? Is it not greater and more 
worthy the idea we ought to haveof the Creator, 
to suppose that there every where exists beings 
who acknowledge his power and celebrate his 
glory, than to depopulate all the universe, ex- 
cepting the earth, and to despoil it of all be- 
ings, by reducing it to a profound solitude, in 
which we should only find a desart space, and 
frightful masses of inanimate matter. 

Since the heat of the sun is so small on the 
earth, and other planets, it is necessarj^ that 
they should possess a heat belonging solely to 
themselves, and our enquiry must be to see 
whence this heat proceeds which alone can 
constitute in them this element of fire. Now 
where shall we be able to discover this ffreat 
quantity of heat if it be not in the source itself, 
in the sun alone ? for the matter of which the 
planets have been formed and projected by a 
like impulsion will have preserved their mo- 
tion in the same direction, and their heat in 



proportion to their magnitude and density, 
Whoever weighs these a lalogics, and con-r 
ccives the power cf their relations, will not 
doubt that the planets have issued from the 
sun by the stroke of a comet, because in the 
solar system comets oidy could have power 
and sufficient motion, to communicate a 
similar impulsion to the masses of matter which 
compose the planets. If to all these circum- 
stances we unite that of the innate heat of the 
earth, and of the insufficiency of the sun to 
support nature, we must rest persuaded, that 
in the time of their formation the planets and 
earth were in a state of liquefaction, afterwards 
in a state of incandescence, and ,at last in a 
successive state of heat, always decreasing 
from incandescence to actual temperature, for 
there is no other mode of conceiving the origin 
and duration of this heat peculiar to the earth. 
It is difficult to imagine that the fire, termt^d 
central, can subsist at the bottom of the globe 
without air (that is, v/ilhout its first aliment, 
and from whence this fire should proceed, 
which is supposed to be shut up in the centre 
of the globe), because what origin, what 
source shall we then find for it ? Descarles has 
imagined the earth and planets were only small 
incrusted suns ; in other words, suns entirely 


^S)i: BUFFO n's 

exlinguislied . Leibnitz has not besiiated to prOi- 
nouncetbat the terrestrial globe owes its source, 
and the consistence of its matters, to the elcr 
jinent of fire: yei these two great philosophers 
had not the assistance of these nnmeroiis cir- 
ciiiTistances and observations which have been 
acquired and collected in our days, and whick 
are so well established that it ap j)ears more than 
probable that the earth, as well as the planets, 
•(v^ere projected out of ihx" sun, and being con- 
sequently of a like matter, which was at first in 
a sta(e of liqucfacticm they obeyed the centri- 
fugal power, at the same time that it c6llec(cd 
itself together by that of attraction, which has 
^iven a round form to all the planets under the 
equator, and flattened under the poles, on ac- 
count of the variety of their rotation ; that af- 
terwarcfethis fire being gradually dissipated, 
the benign temperature, suitable to organized 
Jiature, succeeded in difl"erent planets accord- 
ing to the difference of their thickness or den- 
sity. If there should be other particular 
causes of heat assigned for the earth and pLi- 
liets, which might combine with those whose 
<:rffects we have calculated, our results are not 
less curious, nor less usefid to the advancement 
of science; and we shall here only observe, 
that those particular causes may prolong the 
4ime of the refrigeration of the globe, and the 



dnralian of living nature, bejoncl the terms we 
have indicated. 

But I may be asked is this Tlieorj equally as 
well founded in every point %vhic]i serves far 
its basis ; is it certain, according to your ex- 
periments, that a globe, as large as the earth, 
and composed of the same matters, cannot re- 
frigerate from incandescence to actual tempc-* 
rature in less than 74,000 years, and that in 
order to become heated to the point of incan-* 
descencc a 15th of this time, that isdOOO years, 
would be required : and also that it should be 
surrounded all that time by the most violent 
fire ; if so, there are as you say strong presump- 
tions tliat this great heat of the earth could not 
have been communicated to it from a disttince, 
and that consequently the terrestrial matter 
formerly made a part of the mass of the sun ; 
but it does not appear equally proved that i\iQ 
heat of this body on the earth is at present but 
•^ part of the heat of the glgbe. The testimony 
of our senses seems to refute this opinion, 
which you lay down as a certain truth, for al- 
though we cannot doubt that the earth has an 
innate heat, which is demonstrated by its al- 
ways equal temperature, iii all deep places 
where the coldness of the air cannot communi- 
cate; yet does it result that this heat, ^vhicli 


^d6 liu Frog's 

appears of moderate temperature, is gre^tcf 
than that of the sun which seerns to burn us? 

To all these objections I can give full satis- 
faction, but let us first reflect on the nature of 
our sensations. A very slight, and often im- 
perceptible, difterence in the causes which 
affect us, produces considerable ones in their 
effects. Is there any thing which comes nearer 
to extreme pleasure than grief? and who can! 
assign the distance between the lively irritation 
by which we are moved witli delight, and the 
friction which gives us pain ? between the fire 
"which warms and that which burns ? between 
the light which is agreeable to our sight and 
tliat which blinds us? between the savour 
Tvhich pleases our taste and that which is dis- 
agreeable ? between the smell of which a small 
quantily will at first be agreeable and yet 
soon after create nausea ? We must therefore 
cease from being astonished that a small aug- 
mentation of heat, such as ^^ should appear 
so striking. 

I do not pretend positively to assert that the 
innate heat of the earth is really 49 times 
greater than that wdiicli comes to it from the 
su!i : for as the heat of the globe belongs to all 
terrestrial matter, we liave no means of 
separating it, nor consequently any sensi- 


ble and real limits to wlrich wemidit relate it. 
But even if ihe solar heat be grealer or smaller 
than we have supposed, relative to the terres- 
trial heat, our theory would only alter thp. pro- 
portion of tlie results. 

For ei^ample, if we include the whole extent 
of our sensations of the greatest heat to the 
greatest cold, within the limits given by the 
observations of M. Amontons, that is, between 
seven and eight, and at the same time suppose 
that the heat of the sun can alone produce this 
difierence of our sensations, we shall from 
thence have the proportion of 8 to 1 of the in- 
nate heat of the terrestrial globe to that which 
proceeds from the sun ; and consequently the 
compensation which this heat of the sun ac- 
tually makes on the earth, would be |- and the 
compensation which it made in the time of in- 
candescence will have been _a^: adding toge- 
ther these two terms, we have -^ which mul- 
tiplied by 12f, the half of the sum of all the 
terms of the diminution of heat, gives |^J or 
-J for the total compensation made by the sun's 
heat during the the period of 74047 years of 
tlie refrigeration of the earth to actual tempe- 
rature. And as the total loss of the innate 
beat is to tlie total compensation in the same 
ratio as the time of the period of refrigeration, 
roL. X. Q q ^c 


we shall have 25 : 1 » : ; 74047 : 4813 ^\, so 
that the refrigeration of the globe of the earth 
instead of having been prolonged only 770 
years, would have been 4813 ^ years ; which 
joined to the longest prolongation, the lieat of 
the moon would also produce in this supposi- 
tion, would give more than 50OO years. 

If we adopt the limits laid down by M. dc 
Marian, which are from 31 to 32, and suppose 
that the solar heat is no more than -jV of that 
of the earth, ue shall have only \ of this pro- 
longation, about 1250 years, insfead of 770, 
which gives the supposition of -5^ which we 
have adopted. 

But if we suppose that the sun's heat is only 
^^ of that of the earth, as appears to result 
from the observations made at Paris, we should 
have for the compensation of the incandescence 
^^^and ^1^ for the compensation to the end 
of the period of 7407 years of the refrigeration 
of the terrestrial globe to actual temperature, 
and we should find ^jj for the total compensa- 
tion made by the heat of the sun during this 
period, which would give only 154 years, or 
the 5th part of 770 years for the time of the 
prolongation of refrigeration. And likewise, 
if in the place of ^ we suppose that the solar 
heat was -^^ of the terrestrial, we should find 



that the time of prolongation would be five 
times longer, that is 3850 years ; so that the 
more we endeavour to increase the heat ^vhich 
comes to us from the sun relative to that which 
emanates from the earth, the more we shall ex- 
tend the duration of nature, and date the an- 
tiquity of the earth further back; for by sup- 
posing the heat of the sun was equal to the in- 
nate of the globe, we should find that the time 
of prolongation would be S8504 years, which 
consequently gives the earth a greater antiquity 
of38 or 39000 years. 

If we cast our eye on the table which M. de 
Mairan has calculated with great exactness, 
and in which he gives the proportion of the 
heat which comes to us from the sun, to that 
which emanates from the earth in all climates, 
we shall discover a well attested fact, which is, 
that in all climates where observations'havc 
been made, the summers are equal, whereas 
the winters are prodigiously unequal ; this 
learned naturalist, attributes this constant equa- 
lity of the intensity of heat in summer in all 
climates to the reciprocal compensation of the 
solar heat, and from the l»eat of the emana- 
tions of the central fire. 

All naturalists who have employed them- 


selres on this subject agree with me that the 
terrestrial globe possesses of itself a heat inde- 
pendently of that which comes from the sun. 
Is it not evident that this innate heat should be 
equal at every place on the surface of the globe, 
and that there is no other difference in this re- 
spect than that whicli results from the swelling 
of the earth at the equator, and of its flatness 
under the poles ? A difference, which being in 
the same ratio nearly as the two diameters, 
does not exceed yto^ so that the innate heat of 
the terrestrial spheriod must be ^-^ times 
greater under the cqua'or than under the poles. 
The depcrdition which is made, and the time 
of refrigeration must, therefore, have been 
quicker, or more sudden, in the northern cli- 
mates, where the thickness of the globe is not 
so great as in the southern climates, but this 
difference of -2 |o cnnnot produce that of the in- 
equality of the central emanations, whose rela- 
tion to the heat of the sun in winter being 
equal 50 to 1 in the adjacent climates to tlie 
equator, is found double to the 27th degree, 
triple to the SSth, quadruple to the 40Lh, ten- 
fold to the 49th, and 35 time§ greater to the 
60th degree of latitude. This cause, which 
presents itself, contributes to the cold of (he 



novtlicrn climafcs, but it is insufficient for tbe 
effect of the inequality of the winters, since 
this effect would be S5 times ^eater than its 
cause to the 60th degree, and even excessive in 
climates nearer the poles ; at the same time it 
would in no part be proportional to this same 

On the other hand there is not any founda- 
tion for supposing" that in a globe which has re- 
ceived, or which possesses a certain di^grce ef 
Jieat, there might he some parts of it much col- 
der than others. We are sufficiently acqtiaint- 
«d with the progress of heat and the pheno- 
mena of its communication, to be convinced 
that it is every Avhere distributed alike, since 
by placing a cold body on one thai is hot, the 
latter will communicate to the other sufficient 
heat to render heat of the same degree of tem- 
perature in a short time. It must not, there- 
fore, be supposed that towards the polesthere 
are strata of colder matters less permeable to 
the heat than in other climates, for of whatever 
uature (hey may be supposed to be, experience 
has demonstrated that in a very shovi tunc 
they would become as hot as the rest. 

It is evident that great cold in the north does 
not proceed from tliese pretended obstacles 
which might oppose t!i em selves to the issue of 
heat, nor from the slight difference which that 



oftlie diameters of the terrestrial spheroid must 
produce ; but it appears to me, after much rc- 
lleciion upon it, that we ought to attribute the 
equality of the summers, and the great inequa- 
lity ofthe winters to a much more simple cauf-e, 
but which, notwithstanding, has escaped the 
notice of all naturalists. 

it is certain that as the native heat of the 
earth is much greater than that which comes 
to it from the sun, the summers ought to appear 
nearly equal every where, because this same 
heat from the sun makes only a small augmen- 
tation to the stock of real heat which the earth 
possesses ; and consequently if this heat issu- 
ing from the sun, be only * ofthe native heat 
of the globe, the greater or less stay of it on the 
horizon, its greater or less obliquity on the cli- 
mate, and even its total absence, would only 
produce one-fiftieth difference on the tempera- 
ture of the climate, and hence the summers 
must appear, and are, in fact, nearly equal in 
all the climates of the earth. But what makes 
the winters so very unequal is the emanations 
of this internal heat of the globe being in a 
great measure suppressed as soon as the cold 
and frost bind and consolidate the surface of 
the earth and waters. 

This heat which issues from the globe, de- 
creases in the air in proportion, and in the 



same ratio as the space increases, and the sole 
COHdensation of the air by this cause is sufficient 
to produce cold winds, which acting against 
the surface of the earth, bind and freeze it. 
As long as this confinement of the external 
strata of the earth remains, the emanations of 
the internal beat are retained, and the cold ap- 
pears to be, nay in fact is, very considerably 
increased by this suppression of a part of this 
heat: but as soon as the air becomes milder, and 
the superficial strata of the globe loses its ri- 
gidity, tlie heat, retained all the time of the 
frost, issues out in greater abundance than in 
climates where it doet not freeze, so that the 
sura of the emanations of the heat becomes 
equal and every where alike ; and this is the 
reason that plants vegetate quicker, and the 
harvest is reaped in much less time in northern 
countries ; and for the same reason it is, that 
often at the beginning of summer we feel sucfe 
considerable heats. 

If there were any doubt of the suppression of 
the emanations of the internal heat by the ef- 
fect of frost, we might easily be convinced of 
the fact ; for it is a circumstance universally 
known, that after a frost, we may perceive 
snow to thaw in pits, acqueducts, cisterns, 
quarries, subterraneous vaults or mines, wlien 
even these depths, pits or cisterns, contain no 

water s 

30i BVFFOa^S 

water; the emanations of the earth having 
their free issue through these kinds of vents, 
the ground which covers tliis top is never fro- 
zen so strong as the open land; to the emana- 
tions, it permits their general course, and their 
heat is sufficient io melt the snow, especially in 
hollow places, at the same time that it remains 
on all the rest of the surface where the earth is 
not excavated. 

This suppression ofthe emanations of die na- 
tive heat of the earth h not only made by the 
frost, but likewise by the simple binding of the 
ear 111, often occasioned by a less degree of cold 
thau that which is necessary to freeze the sur- 
face ; there are very few countries where it 
freezes in the plains beyond the 35th degree la- 
titude, particularly in the northern hemisphere. 
It appears, therefore, that from the equator, as 
far as the 35th degree, the emanations of the 
terrestrial heat having always their free issue, 
there ought to be in that part little or no dif- 
ference between winter and summer, since this 
diflbrence proceeds only from two causes, both 
too slight to produce any sensible effect. The 
iirst cause is the difference of the solar action, 
but as this action is itself much smaller than 
that of the terrestrial heat, its difference is too 
inconsiderable to be regarded as any thing. 
The second cause is the thickness of the globe, 



\\luch towards the Soth degree, is near -^lotli 
part less than at the equator, but even this dif-. 
ferencecan only produce a very slight effect, 
since at 35 degrees the relation of the emana- 
tions of the terrestrial to the solar heat is in 
summer from 33 to 1, and in winter from 153 
to 1, which gives 186 to 2 or 93 to 1. From 
hence it can only be owing to the consolidation 
of the earth occasioned by the cold, or even to 
the cold produced by the durable rains -which 
fall in these climates, that wc can attribute this 
difference between winter and summer ; the 
binding of the earth by cold suppresses a part 
of the emanations of the internal heat, and the 
cold, always renewed by the fall of rain, di- 
minishes its intensity ; these two causes, there- 
fore, together produce the difference between 
winter and summer. 

After having proved that the heat which 
comes to us from the sun is gready inferior to 
the native heat of our globe ; after having ex- 
plained that, by supposing it only -^Jg^ part, the 
refrigeration of the globe to actual tem.perature 
cannot be made but in 75,832 years ; after 
having demonstrated that the time of this re- 
frigeration would still be longer, if the heat 
sent from the sun to tlie earth were in a greater 
relation, namely, of J5. or-j^ instead of ^Vj ^ve 
VOL. X. R r cannot 

503 uufpon's 

cannot Ijeblamed for having adopted that pi*o- 
portion which appears the most plausible from 
physical reasonings, and at the same time the 
most probaHe, as it does not extend too fer 
back the time of the commencement of nature, 
which we l3a\'« fixed at 37 or 38,000 years, 
dating itfrom the first day. 

1 nevertheless acknowledge that this time, 
all considerable as it is, does not appear suffi- 
ciently long for certain changes, certain suc- 
cessive alteiations, which Natural History de- 
monstrates to have taken place, and which 
seem to have required a still longer course of 
centuries ; and from which I should be inclined 
to imagine, that, in reality, this time would be 
increased perhaps double if every phenomena 
were completely investigated ; but 1 have con- 
fined myself to the least terms, and restrained 
the limits of time as much as possible, with- 
out contradicting facts and experiments. 

This theory, perhaps, may be attacked by 
another objection, which it is right to guard 
against. It may be told me that I have sup- 
posed, after Newton, the heat of boiling water 
to be three times greater than that of the sun 
in sTtmmer,and iron heated red-hot eight times 
greater ih&n boiling water, that is, 24 or 2a 
times greater than that of tlie adtml tempera- 


ture of the earth, and that there is EometUing 
hypothetical in this supposition, on which I 
have founded tlie second basis of my calcula- 
tions, whose results would be, without doubt, 
very different if this red heat of iron, or glass 
in incandescence, instead of bein^, in il^ct, 25 
times greater than the actual heat of the 
globe, were, for example only 5 or Q times 
as great. 

The better to feel the force of this gbjectiou, 
let us make a calculation of the refrigeration 
of the earth, upon the supposition that in the 
time of incandescence it was only five times 
hotter than it is according to our calculations ; 
this solar heat, instead of a compensation of 
5V would have only made the compensation 
of -5^1^ in the time of incandescence, these two 
terms added together gives ■^-^, which multi- 
plied by 2|, the half of the sum of all the 
terms of the diminution of heat, gives ^ for 
the toktal compensation which the heat of the 
sun has made during the whole period of the 
deperdition of the innate heat of the globe, 
which is 74047 years : therefore we shall have 
: ^^^ : : 74047 : S$8 44 from which we see 
that the prolongation of refrigeration, which 
for a heat 28 times greater than actual tempe- 
rature, has been only 770 years, should have 

308 buffon's 

been 888 |4j i" ^'^e supposition that this first 
lieat should have been only fivie times greater 
thsfn this actual temperature. This alone 
shews us that if we even suppose this primitive 
heat below 25, there would only be a longer 
prolongation of the refrigeration of the globe, 
and that alone appears to me sufficient to 
satisfy the objection. 

It may likewise be said, " you have calcu- 
lated the duration 6f the refrigeration of the 
planets, not only by the inverted ratio of their 
diameters, but also by the inverted ratio of 
their density ; this might be well founded if we 
could imagine that in fact there exists matter 
whose density is as different from that of our 
globe : but does it exist? What, for example, 
willbethe matter of which Saturn is composed, 
since its density is more than five times less 
than that of the earth ? 

To this I answer, that it would be very easy 
to find, in the vegetable class, matters five or 
six times less dense than a mass of iron, mar- 
ble, hard calcareous stone, &c. of which we 
liuow that the earth is principally composed ; 
but without quitingthemineralkingdom, and 
considering the density of these five matters, 
we have 21 f| for iron, 8yf for white marble, 
forgres 7 14, for common marble and calcare- 
ous stone 7 f|; taking the mean term of the 



densities of these five matters, of Vyhic)i the 
terrestrial globe is principally composed, we 
find its density to be 10y\.. It is therefore rcr 
quired to find a matter Avhose density is in the 
relation of 189 to 1000 density, Avhicli is the 
same as that between Saturn and tlie Earth. 
Now this matter might be a kind of pumice 
stone, somewhat less dense than common pu- 
mice stone, whose relative density inhere ly| ; 
whence it appears that Saturn is principally 
composed of a light matter similar to pumice 

So likewise the density of the Earth being 
to that of Jupiter as 1000 to 292, we must 
suppose that Jupiter is composed of a more 
dense matter than pumice stone, but much less 
dense than chalk. 

The density of the Earth being to that of the 
Moon as 1000 to 702, this secondary planet 
appears composed of a matter whose density- 
is not quite so great as that of hard calcareous 
stone, but more so than soff. 

The densitj' of the Earth being to that of 
Mars as lOOO to 730, this planet must be com- 
posed of a matter somewhat more dense than 
that of gres, and not bO great as that of white 

But the density of the Earth being to that of 
Yenus as lOOO to 12700, it may be supposed 


310 buffon's 

that this planet is chiefly composed of a more 
dense matter than emery, and less dense than 

Finally, tlie density of tlie Earth being to 
that of Mercury : : 1000 : 2040, or : : 10^ : 

^SOjI^I^I, it must be thought that this planet is 
composed of a matter less den^se than iron but 
more so than tin. 

To the question, how can animated nature, 
which you suppose every >vhere established, 
exist in planets ofiron, emery, or pumice stone? 
I shall answer, by the same causes, and by the 
same means as it exists on the terrestrial globe, 
although composed of stone, grcs, marble, 
iron, and glass. There are other planets like 
our globe, v/hose principalis one of these mat- 
ters ; but the external causes will soon have 
altered its superficial strata, and according to 
the different degrees of heat or cold, dryness or 
humidity, they will have converted this matter 
into a fertile earth proper to receive the seeds 
of organized nature, which only needs heat and 
moisture to develope itself. 

Having answered the most obvious objec- 
tions, it is necessary now to explain the facts, 
and observations, by which we are assured that 
the sun is only an accessory to the real heat, 
which continually emanates from the globe of 


(be earth; and it will be just, at the same 
time, to see how comparable thermometers 
have taught us in a certain manner that the 
heat in summer is equal in all the climates of 
the earth, excepting Senegal, and some other 
parts of Africa, where (he heat is greater than 

It may be incontcslibly demonstrated, that 
the light, and consequently the heat of the 
sun, emitted on the earth in the summer, is 
very great, comparatively with (hat emitted by 
the same body in winter; and yet, by very 
exact and reiterated observations, thediiFerence 
of the real heat of the sun in summer is very 
small. This alone would be sufficient to prove 
that the heat of the sun makes only a small 
part of that of the terrestrial globe; but in ad- 
dition io this M. Amontons, by receiving the 
rays of the sun on the same thermometer in 
summer and winter, observed that the greatest 
heat in summer in our climate differs from the 
cold in winter, when the water congeals, as 
only 7 differs from 6 ; whereas it can be de- 
monstrated that the action of the sun in sum- 
mer is about 6C) times greater than that of th« 
sun in winter ; it therefore cannot be doubted, 
that there is a fund of very great heat in the 
terrestrial globe, on which, as a basis, the de- 

512 buffon's 

grccs of heat iirise, and that at the surface it 
docs not give a greater quantity of heat than 
that which comes from the sun. 

If it be asked, how we can then assert that 
the heat in summer is 66 times grater than that 
in winter in our climate? I cannot give a bet- 
ter answer than by referring to the memoirs 
given by the late M. de Mairanin 1719, 1722, 
and 1765, and inserted in those of the Aca- 
demy, where he examines, with a scrupulous 
altention, the vicissitudes of summers in dif- 
ferent climates ; the various causes for which 
may be reduced to four principal ones : 1 . The 
inclination under which the light of the sun 
falls according to the different height of (he 
sun on the horizon ; 2Jly. The greater or less 
intensify of light in proportion us its passage 
in the atmosphere is more or less oblique ; 
,*^dly. The diffbrent distance of the earth 
to the sun in summer and winter; and 
4thly. The inequalities of the length of days 
in diiferent climates. By the principle that 
lieat is proportional to the action of light it 
will be easily demonstrated^ that these four 
united causes, combined and compared,' 
diminish with respect to our climate, this 
action of the sun's heat in a ratio of about 
66 to 1 between the summer and the winter 

solstice ; 


solstice ; and this theoretical truth may be re- 
garded as certain, as the second truth from 
experience, and which demonstrates, by the 
observations of ihe thermometer, immediately 
exposed to the sun's rays in winter and sum- 
mer, that the diiference of real heat in these 
two is, nevertheless, at most only from 7 to 6; 
I say at most, for this determination given by 
M. Amontons is not nearly so exact as that 
which has been made by M. de Mairan, who, 
after a great number of final observations, 
proves that this relation is only as 32 to 31. 
What, therefore, must indicate this prodigious 
inequality between these two relations of the 
action of the soldr heat^ in summer and winter, 
which is from 66 to 1 ; and of that of the real 
heaty which is only from 32 to 3i ? Is it not 
evident that the innate heat of the globe of the 
earth is considerably greater than that which 
comes to us from the sun ? It appears, in fact, 
that in the climate of Paris this heat of the 
earth is 29 times greater in summer, and 491 
times greater in winter than thatof ths sun, as 
M. de Mairan has determined it. But I have 
already said that we must not conclude, from 
these two combined relations, tho real one of 
the beat of iht globe of the earth to that 
which comes from the sun, and I have firiven 
reasons which hr\ve determined rae io suppose 
VOL. X. Ss that 

SI^ buffon's 

that we may estimate this heat of the sun 49* 
times less than the heat which emanates from 
the earth. 

From the year ITOl to 1756 inclusive, a 
variety of observations were made with ther- 
mometers, and the following were the results . 
The greatest degree of heat, and of cold, which 
was experienced at Paris in each year was col- 
lected ; a total of these was made, and it was 
found that the mean estimate, in all the ther- 
mometers, reduced to Rheaumur's division, 
was 1026, for the greatest heat in summer, that 
is 26 degrees above the freezing point ; and 
that the mean degree of cold in winter, during 
those 56 years, was 994, or 6 degrees below 
the freezing point of water, whence we con- 
cluded that the greatest heat in our summers 
at Paris differs from the greatest cold of our 
winters only •g?^, since 994 : 1026 : : 31 : 32; 
and it was on this foundation that we stated 
the latter to be the relation of the greatest heat 
to the greatest cold. But it may be objected 
against the precision of this valuation, the de- 
fect of the construction of the thermometer, 
and Rheaumur's division (to which we have 
here reduced the scale of all the rest); and 
this defect is extending only 1000 degrees be- 
low that of ice, as if 1000 degrees were in fact, 
that of absolute cold, whereas absolute cold 



does not exist in nature ; and that of the smallest 
heat should be supposed 10,000 instead of 
1000, which would alter the thermometer's 
gradation. It may likewise be said that it is 
possible all our sensations between the greatest 
heat and the greatest cold are comprised in as 
small an interval as that of a unit on 32 of heat, 
but that the voice of judgment seems to be 
raised against this opinion, and tells us this 
limit is too confined, and that it is much easier 
to reduce this interval than to give it an eighth, 
or a seventh instead of a thirty-second. 

But be this valuation as it may, there can 
be no doubt of the truth of these facts which 
we have drawn from our observations, for in 
the same manner as we found, from the com- 
parison of oQ successive years, the heat of sum- 
mer at Paris 1026, or 2o degrees above the 
freezing point, we also found, with the same 
thermometers, that the heat in summer was 
1026 in every climate of the earth, from the 
equator to the polar circle ;* at Madagascar, in 
the islands of France and Bourbon, Roderigo, 
Siam, and the East-Indies ; at Algiers, Malta, 
Cadiz, Monlpelier, Lyons, Amsterdam, Upsal, 
Petcrsburgh, and as far as Lapland, near the 


* See the Memoirs of Rheaumur In those of the Aca- 
demy (year 1735 and 1741), and also of the Memoirs of 
M. de Mairan in thvseof the year 1765, p. 213. 

316 BUFFO N'S 

polar circle. At Cayenne, Peru, Martinica, 
Carthag^nain America; at Panama; m short, 
in all the climates of tlie two hemispheres and 
continents Tvhere observations could be made, 
it has been constantly found that the liquor of 
the thermometer rose equally to 25, 26, or 27 de- 
grees in the hottest days in summer ; and hence 
ensues the incontestible fact of the equality of 
beat in summer in all climates of the earth. 
There are indeed some exceptions, for at Sene- 
gal, and some few other places, the thermo- 
meter rises 5 or 6 degrees higher, to 31 or 32 
degrees; but that arises from accidental and 
local causes, which do not alter the truth of the 
observations, nor the certainty of the general 
fact, Vvhich alone might demonstrate to ns, that 
there really exists a very great heat in the ter- 
restrial globe, that the effect, or the emana- 
tions, of which are nearly equal in all the 
points of its surface, and that the sun, very far 
from being the only sphere of heat which ani- 
mates nature, is at best only the regulator. 
This important fact, which we consign to pos- 
terity, will enable it to discover the real pro- 
gression of the diminution of the heat of the 
terrestrial globe, which we have been only able 
to determine in a hypothetical manner. In a 
few centuries, I am confident it will be found 



that the greatest beat of summer, insteail of 
raising the liquor of the tliermometer to 26, 
will not raise it to more than 25, or 24 ; and 
from this eilect, which is the result of all the 
combined causes, a judgment may be formed 
of the value of each of the particular causes, 
which produce the total effect of heat oi\ the 
surfiice of the globe ; for the heat which be- 
longs to the earth, and which it has possessed 
from the time of incadescence, has very con- 
siderably diminished, and will continue to di- 
minish with the course of time: this heat is 
independent of that whicli comes from the sun; 
the latter may be looked upon as cuiistant, and 
consequently in futurity will make a greater 
compensation than at present. To the loss of 
this innate heat of the globe there are two 
other particular causes, which may add a con- 
siderable quantity of heat to the effect of the 
two first, tlie only ones we have as yet taken 
notice of. 

One of these particuhtr causes proceeds, in 
some measure, from the iirst general cause, and 
may add something to it. It is certain Ih^it 
during the time of incadescence, aiRl indeed 
all the subsequent tig^^s till that of the refrige- 
ration of the eartli, not any of the volatile 
matters could reside at the surface, or even in 


5iS buffon's 

the internal part, of the globe ; (hey were 
raised and dispersed in the form of vapours,ancl 
could not deposit themselves but successively 
in jiroportion as it cooledjby which means some 
of these matters have penetrated through the 
clefts and crevices of the earth to great depths, 
in an infinity of places; and this is the primitive 
foundation of volcanos, which are all found in 
lofty mountains, were the clefts of the earth 
are so much the greater as these points of the 
globe are more projecting and isolated. This 
deposit of the volatile combustible matters of 
the first ages will have been greatly augmented 
by the addition of every combustible matter 
which has been subsequently formed. Pyrites, 
sulphurs, coal, bitumen, &c. have penetrated 
into the principal cavities of the earth, and 
produced almost every where great masses of 
inflammable matters, and often conflagrations, 
■which have been manifested by earthquakes, 
crruptions of volcanos, and by the hot springs 
which flow from mountains, or run internally 
in the cavities of theearth. It may, therefore, 
be presumed that these subterraneous fires, 
some of which burn without explosion, and 
others with great noise and violence, somewhat 
increase the general heat of the globe. Never- 
theless this adiiition of heat can be only very 



slight, for it has been observed that it is nearly 
as cold on the top of volcanos as on the top of 
other mountains of the same height, except at 
the very time when the volcano throws out in- 
flamed vapours or burning matters. 

The second cause, which seems not to have 
been thought of, is the motion of the moon 
round the earth. This secondary planet per- 
forms its evolution round the earth in 27 days 
and one third, and being 85.3^5 leagues dis- 
tance, it goes over a circumference of 536,329 
leagues in this space of time, which makes a 
motion of 817 leagues in an hour, or from 13 
to 14 leagues in a minute. Although this rout 
is, perhaps, the slowest of all the celestial bo- 
dies, yet it is rapid enough to produce on the 
earth, which serves for the axis or pivot to this 
motion, a considerable heat by the friction 
which results from the weight and velocity of 
this planet. But it is not possible to estimate 
the quantity of heat produced by this exterior 
cause, because hitherto we have had nothing 
which might serve us for a term of comparison. 
But if we ever can discover tlie number, mag- 
nitude, and velocity, of all tlie planets which 
circulate round the sun, we s^IialUhen be able 
to judge of the quantity of iieat wliich the 
moon can give to tlic earth, by the much 


390 buffon's 

grealer quantity of fire which all these vast bo«* 
dies excite in the sun. For my own part I am 
greatly inclined to think that the heat produc- 
ed by this cause in the globe of the earth, 
forms a verj' considerable part of its own heat : 
and that, in consequence, we mast still extend 
the limits of time for the duration of nature. 
But let us return to our principal object. 

We have observed that the summers are very 
nearly equal in all climates of the earth, and 
that this truth is founded on incontestible 
facts ; but it is not the same with respect to 
winters ; they are very unequal, and vary in 
different climates, as we remove further from 
that of the equator, where the heat in winter 
and summer is nearly the same. I think I 
have already explained in a satisfactory man- 
ner the cause of this, viz, the suppression of the 
terrestrial heat. This suJ)pression is, as I 
have said, occasioned by the cold winds, which 
fall from the air, bind the earth, freeze the 
waters, and shut up the emanations of the 
terrestrial heat during the time the frosts re- 
main ; so that it is not at all surprising that the 
cold in winter is in fact so much the greater 
as we advance further towards the climates 
where the mass of air, receiving the rays 



of the sun more obliquely is for that reason 

But with respect to the cold as well as to 
the heat, there are some countries which are an 
exception to the general rule. At Senegal, 
Guinea, Angola, and probably in every 
country where the natives are black, as in 
Nubia, the country of the Papons, New Gui- 
nea, &c. it is certain that the heat is greater 
there than in any other part of the earth ; but 
this arises from local causes and therefore in 
those particular climates where the east wind 
reigns during the whole year, passes over a 
very considerable track of land, and receives 
a scorching heat before it arrives to them, it is 
not surprising that the heat is found 5, 6, and 
even 7 degrees greater tlian it is elsewhere. 
The excessive colds of Siberia, are also to be 
attributed to that part of the surface of the 
globe being much higher than that which sur- 
rounds it. " The northern Asiatic countries 
(says the Baron Strahlenberg in his description 
of the Russian Empire) are considerably more 
elevated than the European. They are like 
a table, in comparison of the bed on which 
they appear so be placed ; for on coming from 
the west and leaving Russia, we pass to the 
east by the mountains Ripha and Rymnikas 
VOL. X. T t to 

322 BUFFO. \'S 

to enlcr Siberia, and constantly advance to an 
ascent." " There are many places in Siberia, 
says i\I. Gmelin, which arc not less elevated 
above the rest of the earth, nor less remote 
from its centre, than are many high moun- 
tains in many other regions." Tliese plains of 
Siberia, appear, in fact, to be as high as the 
summit of theRiphean mountains, on which 
the ice and snow do not wholly melt during 
summer ; and if the same effect do not hap- 
pen in the plains of Siberia, it is because they 
are less detached, for this local circumstance 
also adds much to the duration and to the in- 
tensity of cold and heat. A vast plain once 
made hot will retain its heat longer than a de- 
tached mountain, though both are alike ele- 
vated ; and for the same reason the mountain 
once cooled will retain its snow or ice lon- 
ger than the plain. 

But if we compare the excess of heat with 
that of cold produced by these particular and 
local causes, we shall be surprized to find, that 
in Senegal, &c. where the heat is greatest, it ne- 
ver exceeds seven degrees beyond the summer 
heat in other countries, which is 26 degrees 
above the freezing point, while on the contra- 
ry, the colds of Siberia sometimes reach 60 or 
70 degrees below it, and that at Petersburg!), 



Upsal, &c. under the same latitude as Siberia, 
the greatest cold is not more than to 25 or 26 
degrees below tbe freezing point ; therefore, 
we must conclude, that these local causes have 
much more influence in cold than in hot cli- 
mates. Although we cannot pretend to deter- 
mine what this great difference in the excess 
of cold and heat may produce,yet by reflecting 
on it, it appears that we may easily conceive 
the reason of this difference. The auirmenta- 
tion of the heat in such a climate as Senegal 
can only proceed from the action of the air^ 
the nature of the soil, and the depression of 
■the ground; forthis country being alnwst on a 
level with the sea, it is in a great measure co- 
vered with scorching sands, over which an 
jeasterly wind continually blows ; this, instead 
of refreshing the air, only renders it more burn- 
ings because it traverses over more than 2000 
leagues of land in its way, and consequently 
acquires a considerable degree of heat. But 
in such countries as Siberia, where the plains 
are elevated like the summits of mountains 
above tbe level of the rest of the eaith, this 
sole diftbrence of elevation must produce an ef- 
fect proportionally greater than the depression 
of the ground of Senegal, which cannot be 
s,upposed more than that of the level of the 

324: • buffon's 

sea ; for if the plains of Siberia be only elevate 
ed 4 or 500 fathoms above Ibe level of Upsal, 
or Petersburgh, we must cease from being as- 
tonished that the excess of cold is so great 
there ; sine? the heat which emanates from the 
earth, decreases at each point as the space in* 
creases, and this elevation of tlie ground alone 
suffices to explain this great difference of cold 
under the same latitude. 

On this point there remainsonly oneinterest- 
ing question. Men animals, and plants, may, 
for some time, support the rigour of this cold, 
which is 60 degrees below the freezing point ; 
but could theyalso support a heat which should 
be CO degrees above it ? To tliis we answer, 
yes, provided we knew as well how to guard 
airainst the heal as we do to shelter ourselves 
from the cold ; and if the air could, during the 
remainder of the year, refresh the earth, in the 
same manner as the emanations of the heat of 
the globe warms the air in cold countries. We 
know of plants, insects, and fish, which live 
and grow in baths of 45, 50, and even 60 de- 
grees of heat ; there are, therefore, species in 
living nature which can support this degree 
of heat ; and as the negroes are in the human 
race those whom a strong heat the least in^ 
commodes, might we not conclude, according 



to this hypothesis, that the earth has continued 
to decline from its original heat, and that the 
race of negroes are more ancient than that of 
white people? 



NATURE is that system of laws established 
by the Creator for regulating the existence of 
bodies and the succession of beings. Nature 
is therefore not a body, for if it were so, it 
would comprehend every thing; neither is it a 
being, for in that case it would necessarily be 
God. We must rather consider Nature as an 
immense living power, which is in subordina- 
tion to the Supreme Being, and by his com- 
mand animates the universe, and whose actions 
are dependent on, and continued by, his con- 
currence or consent. This power is that part 
of Divine omnipotence which is manifested to 

mankind ; 


mankiiid : it is the cause and eflfcct, tho mode 
and substance, the design and execution. Ex- 
tremely different from all human art, whose 
productions are inanimate. Nature is herself a 
Mork perpetually alive, an active, an unceas- 
ing operator, who knows how to make use of 
every material, and whose power, though al- 
ways employed on the same invariable plan, in- 
stead of suffering dirainulion, is perfectly in- 
exhaustible : time, space, and matter, are her 
means ; the universe her object ; and motion 
and life her end. 

Every object in the universe is the effect of 
this power. Those springs which she makes 
use of are active forces which time and space 
can only limit but can never destroy; forces 
which unite, balance, and oppose, but areinca-r 
pable of annihilating each other. Some pcr 
netrate and connect bodies, others heat and 
animate them. It is principally by attrac- 
tion and impulsion, that this power acts 
upon brute matter, while beats and organic 
molecules are her chief active agents, which 
she employs in the formation and exj an- 
sion of organized beings. Aided by such in- 
struments, how can the operations of Nature 
be limited ? She only wants the additional 
power to create and annihilate to become omni- 
potent. But these two extremes the Almighty 



has reserved to himself alone ; the power of 
creating and annihilating are his peculiar at- 
tributes; while that of changing, destroying-, 
unfolding, renewing, and producing, are th€ 
only privileges he has conferred on this or any 
other agent. Nature, the minister of his irrc^ 
"cocahle commands, the depositary of his immU' 
table decrees, never deviates from the laws he 
has prescribed to her ; she never changes any 
part of his original plan, but in all her opera- 
tions she exhibits the will and design of the 
eternal Lord of the universe. This grand de- 
sign, this unalterable impression of all exist- 
ence, is the model upon which she invariably 
acts; a model of which all the features are so 
strongly impressed, that they can never be 
effaced; a model which the infinite number 
of copies, instead of impairing', only serve t(3 

We may therefore affirm that every thing 
has been created, but nothing annihilated; 
Naiure acts between the two without ever 
reaching either the one or the other. It is in 
some points of this vast space, which she haj» 
filled and traversed from the beginning of ages, 
that we must endeavour to lay hold of her (o 
bring her inio view. 

Whatan infinity of objects, comprehending 
jin infinity of matter, which would liave beeu 


o28 BUFFO n'S 

created in vain, had it not been divided info 
portions, separated from each other by almost 
inconceivable spaces ! Myriads of luminous 
globes, placed at immense distances, are the 
bases which support the fabric of the universe, 
and millions of opaque globes, which circu- 
late round them, constitute the moving order of 
its architecture. By two primitive forces, each 
of which are in continual action, these masess 
are revolved and carried through the immen- 
sity of space ; and their combined efforts pro- 
duce the zones of the celestial spheres, and in 
the midst of vacuity establish fixed stations, and 
regular routes and orbits.. From motion pro- 
ceeds the equilibrium of worlds, and the repose 
of the universe. The first of these forces is 
equally divided, but the second is separated in 
unequal proportions. Every atom of matter 
contains the same degree of attractive forcc^ 
while every individual globe has a different 
quantity of impulsive force assigned to each. 
Of the stars, some are fixed and others wan- 
dering ; some globes appear formed to attract, 
and others to impel or be impelled. Some 
spheres have received a common impulsion in 
the same direction, and others a particular 
impulsion. Some stars are alone, and others 
are attended by satellites ; some are luminous, 



E^nd others opaque masses. There are planpt^ 
whose different parts successively enjoy a bor- 
rowed light, and there are comets which, after 
being lost in the immensity of space for several 
ages, return to receive the influence of the solar 
heat. There are some suns which appear and 
disappear as if they were alternately kindled 
and extinguished ; and there are others which 
n^erely shew themselves and then are seen no 
ipore. Heaven abounds with great events, 
which the human eye is scarcely able to per- 
ceive. A sun which expires and annihilates 
a world, or system of worlds, has no other 
effect upon the eyes of man than an i^ms- 
fatuus, which gives a transitory bla?;e and 
then vanishes for ever. Mao, confined to the 
terrestrial atom on which he vegetates, cpn^ 
aiders this atom as a world, and loojks upoi; 
pther worlds as atoms. 

This earth which we inhabit js scarcely dis- 
tinguishable among the other globes, and per- 
fectly invisibl,e to the distant spheres ; it is at 
least a million times smaller than the sun by 
which it is illuminated, and even a thousancj. 
times less tlian some of the planets which, by 
its influence, the sun compels to ciiculate 
round him. Saturn? Jupiter, Mai^j the Earthy 
Yenus, Mercury, an,d the Sun, occupy that 
\oh. X. U u small 

330. BUFFO n's 

small portion of the heavens which we tertrj^ 
our Universe. These planets, with their sa- 
tellites, moving with amazing celerity in the 
same direction, and almost in the same plane, 
compose a wheel of an immense diameter, 
whose axis supports the whole weight, and 
which by the rapidity of its own rotation must 
inflame and diffuse heat and light throughout 
the whole circumference. As long as this re- 
gular motion continues (and which will be 
eternal, unless the Divine Mover exert the 
same force to destroy as He thought necessary to 
create them) the sun will burn and illuminate 
all the spheres of this universe with his splen- 
dor; and as, in a system where the whole of 
the bodies mutuatly attract each other, nothing 
can be lost or removed without being return- 
ed, the quantity of matter must always remain 
the same ; this great source of light and life 
can never be extinguished or exhausted, for 
other suns, which also continually dart forth 
their fires, constantly restore to our sun as 
much light as they take from him. Comets 
are more numerous than planets, and like 
them depend on the power of the sun ; they 
also press on the common focus, and by aug- 
menting the weight increase the inflammation. 
They may also be said to form a part of our 



liHi verse, for, like the planets, they are subject 
to the attraction of the sun. But in their pro- 
jectile and impelled motions they have nothing 
iji common either with each other or with the 
planets. Every one of them circulates in a 
different plane, and they each describe orbits 
in different periods of time ; for some perform 
their revolutions in a few years, while others 
require several centuries. The sun, simply 
moving round his own centre, remains, as 
it were at rest in the midst, and, at the same 
time, serves as a torch, a focus, and an axis, 
to all and every part of this w onderful ma- 

That the sun continues immoveable, and re- 
gulates the motions of the other globes, is to be 
ascribed to his magnitude alone. The force 
of attraction being in proportion to the mass of 
matter; as the sun is so considerably larger 
than any of the comets, and contains above a 
thousand times more matter than the most ex- 
tensive planet, they can neither derange him 
nor diminish his influence, which extending to 
immense distances keeps the whole within the 
bounds of his power, and thus at particular 
periods recals those which have stretched fur- 
thest into the regions of space. Some of these 
en being brought back, approach so near the 



siin, that after Tiavin^^ cooled for ages they re- 
ceive an inconceivable degree of beat. From 
experiencing- the^ alternate extremes of heat 
artd cold, they ate subject to singular vicissi- 
ttides, as Well as from the ineCfiialities of theur 
tridtioTis, which at sortie titnes are most incon- 
ceivably rapid, and at others so amazingly 
^loiv as to be scarel}^ perceptible. In compari- 
S6n with the planets the comets may be consi- 
dered fes ivorlds in disorder, for to them the 
orbits of the planets are re'gtilar, their move- 
ments equal, their temperature always the 
sanle ; they appear to be places of rest, where, 
every thing being permanent, Nature, has the 
power of establishing a uniform plan of opera- 
tion, and successively to mature her various 
productions. Among the planets the Earth, 
which we inhabit, seems to possess peculiar ad* 
Vantages ; from being less distant from the ^un 
than Saturn, Jupiter, and Mars, it does not ex- 
perience that excess of cold ; nor is it so 
scorched as Venus and Mercury, which appear 
to revolve in an orbit too near the body of that 
luminary. Besides, what a peculiar magnifi- 
cence from Nature does the earth enjoy? A 
pure light, gridunlly extending ftom east to 
west, alternately gilds both hemispheres of this 
globe; which is also surrounded with a pune 



transparent element. By a mild and fertile 
heat all (he germs ofexistence are animated and 
nnfolded, and they are nourished and supported 
by a plentiful supply of excellent waters. Con- 
siderable eminences dispersed over the surface 
of the land, not oaly check, bnt collect the 
moist vapours which float in the air, and give 
rise to perpetual fountains. Immense cavi- 
ties evidently formed for the reception of those 
waters, separate islands and continents. The 
sea in extent is equal to that of the land : nor 
is this a cold and barren element, but a new 
empire, no less rich and no less furnished with 
inhabitants. By the finger of the Almighty 
the limits of the waters are marked out. If 
the sea encroach on the western shores, it re- 
treats from those of the cast. This great 
mass of water, though inactive of itself, is agi- 
tated, and put in motion by the influence of 
the celestial bodies, whence arise its regular 
and const-Hit flux and reflux ; it rises and falls 
with the course of the moon, and is always at 
the highest when the action of the sun and 
moon concurs ; it is from these causes uniting 
at the time of the equinoxes, that the tides arc 
then higher tiian at any other time ; and this 
is certainly the strongest mark of the connec- 
tion of this globe with the heavens. These 


S34 buffon's 

general and constant motions are the cause of 
many variable and particular circumstances ; 
it is by those that the removals of earth are 
occasioned, which falling in the form of sedi- 
ment, produce mountains at the bottom of the 
sea, similar to those which are on the surface 
of the land; they also give rise to currents, 
which following the direction of these chains 
of mountains, bestow On them a figure, whose 
Singles correspond, and maintain a course in 
the midst of the waves as waters run upon 
land ; they may in fact, be considered as sea*- 

The Air being lighter and more fluid than 
water, is subject to the influence of a greater 
number of powers. It is constantly agitated 
by the effects of the sun and moon, by the 
immediate action of the sea, and by the rare- 
faction and condensation of heat and cold. The 
winds arc, as it may be said, its currents ; they 
force and collect the clouds, they give rise to 
meteors, and transport the moist vapours of 
the ocean to the surfuces of islands and conti- 
nents ; from them proceed storms, and they 
diffuse and distribute the fertile dews and rains 
over the land ; they interfere with the regular 
motions ot the sea, agitate the waters, some- 
times stop, and at others precipitate the cur- 


rents, elevate the waves, and excite dreadful 
storms and tempests. Forced by them the 
troubled ocean rises towards the heavens, and 
with a tremendous noise and violence, rushes 
against those immoveable barriers, which it 
can neither destroy nor surmount. 

The earth being elevated above the level of 
the sea, it is thus defended against its irrup- 
tions. Its surface is beautifully enamelled 
with various flowers, and a constant renewing 
verdure ; it is inhabited by numberless species 
of inhabitants, among which, man, placed to 
assist the intentions of Nature, presides over 
every other being, finds a place of perfect re-- 
pose, and a delightful habitation. He alone is 
endowed witli knowledge, and dignified witli 
the fiiculty of admiration ; the Almighty has 
rendered him capable of distinguishing the 
wonders of the universe, and a witness of his 
increasing miracles. Animated by a ray of 
divinity, he participates the mysteries of the 
Deity. It is by this ray tliat he is enabled io 
think and reflect, and that he perceives and un- 
derstands the wonderful works of his Creator. 

The external throne of the Divine mag- 
nificence is Nature ; and man, by contem- 
plating her, advances by degrees to the internal 
throne of the Almighty. He is formed to 


$$6. buffon's 

udore his Creator, and to h^ve dominion ovef 
every other creature; he is the vassal of heaven, 
and the lord of the earth ; by hina this nether 
globe is peopled, enobled, and enriched ; he 
f{>tablishcs order, subordination, and harmony 
among living beings, and even to Nature her- 
self he gives polish, extension, cultivation, ^nd 
embellishment ; for he cuts down the thistle 
und the bramble, and, by his care, multiplies 
the vine and the rose. In those dreary desarts 
vhere man has not inhabited, we find then> 
ever-run wi<h thorns and briars ; the trees de- 
formed, broken and corrupted, and the seeds 
T^hich ought to renew and embellish the scene, 
Rfechaaked by surrounding rubbish, and ret 
dnced to sterility. Nature, whom we find ir^ 
other situations adorned with the splendour of 
youth, has here the appearance ofoldageand 
eiccrepitude. Here the earth , overloaded with 
the spoils of its produciipns, instead pf pre* 
senting a scene of beautiful verdure, exhibit? 
only a rude mass of coarse herbage, and trees 
Joided with parasitical plants, as lichens, aga* 
ri&s, and other impure and corrupted fruits ; 
the low grounds are covered with putrid and 
§<agnant waters ; these miry lands being nei^ 
ther solid nor'fluid, arc not only impassable bujt 
ere entirely useless to the inhabitants of j)qi\}. 



land and ^ater ; and the marshes abounding 
with stinking aquatic plants, serve only to nou- 
rish venomous insectSjand to harbour infectious 
animals. There is, indeed, between the pu- 
trid marshes of the low ground, and the de- 
cayed forests of the high parts of the country, a 
species of lands, or savannas, but which are 
very different from our meadows ; for in them 
there is an abundance of noxious herbs which 
spring up and check the growth of the useful 
kinds : instead of that delicate enamelled turf, 
which may be considered as the down of the 
earth, they are covered over with coarse vege- 
tables and hard prickly plants, which are so 
interwoven, that they appear to have more con- 
nection with each other, than with the soil ; 
and by a constant and successive generation at 
length form a kind of rough mat several feet 
thick* In these uncultivated and desolate re- 
gions,there is no road, no communication, and 
no vestige of intelligence. Man, when seek- 
ing to destroy the wild beasts, is compelled to 
follow their tracks, and to be constantly on 
the watch, lest he should become a victim to 
their savage fury ; alarmed and terrified by 
their frequent roarings, and even awed by the 
profound silence of those dreary solitudes, he 
shrinks backhand exclaims ; '• Uncultivated 
yoL% X. X X Nature 

^^ Nature is bideoiis and onflounsliing ; it is 
" I alone Vihty can render her agreeable and 
*' vivacious. Let us drain the marslies, and 
'* jSrive animation to the waters, by converting 
" them into brooks and canals ; let us make 
*' use of that active and devouring element, 
** whose po'wer we have discovered ; let us 
** apply fire to this burthensome load of vege- 
** tables, and to those decaying forests which 
*' are already half destroyed ; let us complete 
*' the work by destroying w4th iron what can- 
*' not be removed by fire ; and then instead 
" of coarse reeds and water-lilies, from which 
*' the toa<l is said to extract his poison, we 
" shall soon behold the ranunculus, truffles, 
^' and other mild and salutary herbs spring up ; 
*^ that land, which was formerly impassable, 
" will become a flourishing pasture for flocks 
•* of cattle, where they will find plenty of 
" food, and where, by the excellence of their 
^' sustenance, they will increase and multiply, 
*^ and thus reward us for our labours and the 
'' protection we have given them. Let us go 
*^ still further, and subjectthe ox totlie yoke ; 
''let his strength and weight of body be em- 
^' ployed to plough the ground, which ac- 
*' quires fresli vigour from culture. Thus 
♦'will lh« operations.of Nature be assisted, 

'' and 


^^ and acquire double strength and splendor 
^' from the skill and industry of man." 

How beautiful is cultivated Nature I How 
lovelj does she appear when decorated by the 
iiand of man ! He is himself her chief orna- 
ment, her noblest production, and by multi- 
plying his own species he increases the most 
precious of her works. She even seems to 
multiply in proportion to his attention, for 
by his art hedevelopes all that she has conceal- 
ed in her bosom. What a source of unknown 
treasures has been brought to light ! flowers, 
fruits and grains, matured to perfection, and 
xnaltiplied to infinity ; the usual species of 
animals transported, propagated and increased, 
-without number ; the noxious and destructive 
kinds diminished and driven from the habita- 
tions of men ; gold, and iron a more useful 
metal, extracted from the bowels of the earth ; 
torrents restrained, rivers directed in their 
courses and confined within their banks, and 
even the ocean itself subdued, investigated and 
traversed from one hemisphere to the other; the 
earth rendered active, fertile, and accesible, in 
every part 5 the vallies and plains changed into 
blooming meadows, rich pastures, and culti- 
.y^ted §dd& ; tbe hills SHUounded with vines 


310 BUFFON'f 

and fruits, and their summKs crowned with 
useful trees ; the desarts converted into popu- 
lous cities, whose inhabitants spread from its 
Centre (o its utmost extremities; roads and com- 
munications opened, established 5 and frequent- 
ed, as so many proofs of the union and strength 
of society. There are besides a thousand other 
monuments of power and glory ^ which clearly 
demonstrate that man is the lord of the earth ; 
that he has changed and improved its surface; 
and that from the earliest periods of time he 
alone has divided the empire of the world be- 
tween him and Nature. 

It is by the right of conquest, however, that 
he reigns ; he rather enjoys than possesses, 
and it is by perpetual activity and vigilance 
that he preserves his advantage ; if those are 
neglected every thing languishes, changes, 
and returns to the absolute dominion of Na- 
ture, she resumes her power, and destroys the 
operations of man ; envelopes with moss and 
dust his most pompous monuments, and in 
the progress of time entirely effaces them, leav- 
ing him to regret having lost by his negligence 
what his ancestors had acquired by their in- 
dustry. Those periods in which man loses 
his empire, those ages in which every thing va- 
Ittable perishes, commence with war, and are 



completed by famine and depopulation. Al- 
though the strength of man depends solely upon 
the union of numbers, and his happiness is de- 
rived from peace, he is, nevertheless, so regard- 
less of his own comforts as to take up arms and 
to ^ght^ which are never-failing sources of 
ruin and misery. Incited by insatiable avarice, 
or blind ambition, which is still more insa- 
tiable, he becomes callous to the feelings of 
humanity ; regardless of his own welfare, his 
whole thoughts turn upon the destruction of 
his own species, which he soon accomplishes. 
The days of blood and carnage over, and the 
intoxicating fumes of glory dispelled, he be- 
holds, with a melancholy eye, the earth deso- 
lated, the arts buried, nations dispersed, aa 
enfeebled people, the ruins of his own happi- 
ness, and the loss of his real power. 

Omnipotent God ! by whoisc presence Nature 
is supported, and harmony among the laws of 
the universe maintained ; who seest from thy 
immoveable throne in the empyrean all the ce- 
lestial spheres rolling under thy feet without 
deviation or disorder; who, from the bosom 
of repose, every instant renewest their vast 
movements, and who alo:.e governs in profound 
peace an infinite number of heavens and of 
earths, restore, restore tranquillity to a troubled 

world ! 

S42 BUFFO n's 

■world ! Let the earth be silent ! Let the pre» 
snmptaons tunmlts of waranti discon^ Ix^dis* 
pelled by the sound oi thy voice I Merciful 
God I aotbor of ail beiu^, whose . aternal re- 
gards extend to everj created object, and to 
man, thy principal favourite ; thou ba«t illu- 
mined his miad v ith a ray of thy immortal 
light ; penetrate also his heart Wr h a shaft of 
thy love ; thy divine sentiment, when univer- 
sally diffused, viill unite the most hostile 
spirits ; man will no L nger dread the sight of 
man, nor will bis hand any longer coitinue to 
feearmed with murdering steel ; the devouring 
iSames of war "will no longer stop the sources of 
generations; the humaa species, -which are 
BOW weakened, mutilated, and prematurely 
mowed down, will germinate anew, and mul- 
tiply without number. Nature, groaning un- 
tier the pressure erf calamity, sterile and aban- 
defied, will soon resume with additional vigour 
her former fecundity ; and we, beneficent God \ 
%ha\\ aid, cultivate, and incessantly contem- 
plate her operations, that we, at every mo- 
ment, may be enabled to offer thee a fresh tri* 
bute of gratitude and admiration* 




Individuals of whatever kind, or however 
numerous, are of no estimation in (he universe ; 
i«t is species alone that are existences in Nature, 
for they are as ancient and pennancnt as her- 
self. To have a clear and distinct idea of this 
subject we must not consider a species as a 
collection or succession of similar individuals, 
but as a whole, independently of number or 
time, always active, and always the same ; a 
whole which was considered but as one in the 
works of the creation, and therefore constitutes 
only a unit in Nature. Of these units the hu- 
man species is to be placed in the first rank ; 
all the others, from the elephant to the mite, 
from the cedar to the hyssop, belong to the se- 
cond and third orders. Notwithstanding that 
theviirediiFerentin form, substance, and even 
life, yet each sustains its appointed destination, 
and subsists independently of others, while the 
whole, in a general view, represents animated 
Natu»*e, who has hitherto supported, and will 
continue to support, herself in the same man- 
ner as she is seen at present. Her duration is 




not to be estimated by a day, a year, an age, 
iior any given period of time, for time it- 
self relates only (o individuals, to beings whose 
existence is limited. It is not so with respect 
to species, for their existence is constant ; their 
permanence produces duration, and their dif- 
ferences give rise to number. It is in th is 
light that we must consider species, and give 
to each an equal right to the indulgence and 
support of Nature ; for so she has certainly 
considered them, by bestowing on each the 
means of existing as long as herself. 

Let us now consider the species as having 
changed places with the individual. In our 
preceding observations we have seen the 
relation which Nature holds in respect to 
man ; let us now then take a view in what light 
she would appear to a being who represented 
the whole human species. We perceive that 
in the spring the fields renew their ver- 
dure, the buds and flowers expand, the 
bees revive from their state of torpor, the 
swallows return to our climates, the night- 
ingale chaunts her song of love, the lamb 
frisks, and the bull laws with desire, and 
all animated creatures are eager to unite 
and multiply their species ; and we can 
then have no ideas but those of repro- 



duction and the increase of life. But whea 
the dark season of cold and frost approaches, 
these same beings become indifferent to and 
avoid each other ; many of the feathered race 
desert our clime, and the inhabitants of the 
waters lose their freedom under tlie massy con- 
gelations of ice ; various animals dig retreats 
for themselves in the ground, where they fall 
into a state of torpor ; the earth becomes hard, 
the plants wither, and the trees, deprived of 
their foliage, are covered with frost and snow ; 
every object excites the idea of languor and 
annihilation. These apj^arances, however, 
of renovation and destruction, images, as it 
were, of life and death, although they se^m 
general, are only individual and particular. 
Man, as an individual, concludes in this man- 
ner, but tlie being whom we have supposed as 
a representative of the species, thinks and 
judges in a manner more exalted and general ; 
in that constant succession of destruction and 
renovation, and in those various vicissitudes, he 
perceives only permanence and duration. The 
different seasons in one year appear to him the 
same as those of the preceding, the same as 
those of millions of ages. The animal which 
may be the thousandth in the order of genera- 
tion is the same to him as the first. In a 
vot. X. Y y word, 

346 buffon's 

word, if man had no period to Lis existence, 
and if all the beings by which he is surrounded 
existed in the same manner as they do at pre- 
sent, the idea of time would vanish and the in- 
dividual would in fact become the species. 

het us then consider Nature for a few mo- 
ments under this new aspect. Man certainly 
comes into the world enveloped in darkness. 
His mind is equally naked with his body ; he 
is born without knowledge and without de- 
fence, and brings nothing with him but passive 
qualities. He is compelled to receive the impres- 
sions of objects on his organs ; even the light 
shines on his eyes long before he is able to 
recognize it. To Nature he is at first indebt- 
ed for every thing, without making her any 
return. No sooner, however, do his senses 
acquire strength and activity, and he can 
compare his sensations, than he reflects upon 
the universe ; he forms ideas, which he retains, 
extends, and combines. Man, after receiving 
instruction, is no longer a simple individual, 
for he then, in a great measure, represents the 
whole human species. He receives from his 
parents the knowledge which had been trans- 
mitted to them from their forefathers ; and 
thus, by the divine arts of writing and print- 
ing, the present age, in some sort, becomes 



identified with those that are past. This 
accumulation of experience in one man, al- 
most extends the limits of his being to infini- 
ty. He is born no more than a simple indi- 
vidual, like other animals, capable only of at- 
tending to present sensations ; but he becomes 
afterwards nearly the being which we sup- 
posed to represent the whole species ; he reads 
what has past, sees the present, and judges of 
the future ; and in the torrent of time, which 
carries off and absorbs all the individuals of 
the universe, he perceives that the species are 
permanent, and Nature invariable. As the 
relations of objects are always the same, to him 
the order of time appears to be nothing ; he 
considers the laws^ of renovation as only 
counterbalancing those of permanency. An 
uninterrupted succession of similar beings, is, 
in effect, only equivalent to the perpetual 
existence of one of them. 

What purposes then are gained by this im- 
mense train of generations, this profusion of 
germs, many thousands of which are abortive 
for one that is brought into life ? Does not this 
perpetual propagation of beings, which are 
alternately destroyed and renewed, uniformly 
exhibit the same scene, and occupy the same 
proportion in Nature ? From what cause pro- 


ceed all these changes of life and death, these 
laws of growth and decay, all these individual 
vicissitudes, and reiterated representations of 
the same identical thing ? They certainly arise 
from the very essence of Nature, and depend 
on the first establishment of the universal ma- 
chine ; the whole of which is fixed and stable, 
but each of its parts being endowed with the 
power of motion, the general movements of 
the celestial bodies have produced the parti* 
calar ones of this terrestrial globe. The pene- 
trating forces by which these immense bodies 
are animated, and by which they act recipro» 
cally upon each other at a distance, at the 
same time animate every particle of matter ; 
and this strong propensity, which every part 
has towards each other, is the first bond of 
beings, the ground of consistence and perma" 
nency in Nature, and the support of harmony 
in the universe. From these great combina- 
tions the smaller relations are derived. The 
earth moving on its own axis having separated 
the portions of duration into day and night ; 
all its animated inhabitants have their stated 
periods of light and darkness, of their times of 
waking and sleeping. The action of the 
senses, and the motions of the members which 
form a great part of the animal economy, arc 



related to this first combination; for in a 
world where perpetual darkness reigned, 
would there be senses alive to the enjoyment of 

As the inclination of the axis of the earth, 
in its annual course round the sun, produces 
considerable variations of heat and cold, which 
we call seasons, all its vegetables have also, 
either wholly or partially, their seasons of life 
and death. The fall of the leaves, and the 
decay of fruits, the withering of herbs aivd the 
destruction of insects, depend entirely on this 
second combination. In those climates where 
there is not this variation, by the inclination 
not being so material, the life of the vegetable 
is not suspended, and every insect completeg 
the stated period of its existence. Where the 
four seasons, in fact, make but one, as under 
the line, the surface of the earth is constantly 
covered with flowers, the trees have a perpe- 
tual foliage, and Nature seems to enjoy a con- 
tinual spring. 

Both in animals and plants, their particular 
constitution is relatively to the general tempe- 
rature of the earth, and which temperature de-? 
pends upon its situation and distance from the 
sun. If they were removed to a greater dis- 
tance, neither our animals,nor our plant«,could 
live or vegetate ; the water, sap, blood, and 


5j0 buffon's 

all their liquors, would lose their fluidity; if on 
the contrary they were more near they would 
vanish and dissipate in vapour. Ice and fire 
are the elements of death, and temperate heat 
the first support of life. The living particles 
so generally diffused through all organized 
bodies are related, not only by their activity 
]but number, to the particles of light which 
strike and penetrate almost all matter with 
their heat ; for in every place where the sun 
can heat the earth with its rays, the sur- 
face will be covered with verdure, and peopled 
with animals ; even ice is no sooner dissolved 
into water tlian it swarms with inhabitants. 
Water, indeed, is apparently more fertile than 
the earth ; from heat it receives motion and life. 
In one season the sea produces more animals 
than the earth sustains ; but its production of 
vegetables is infinitely less. And because 
that the inhabitants of the oceqin have not a 
a sufficient and permanent supply of vegeta- 
bles, they are compelled to feed upon each 
other ; and it is to this necessity that their 
immense multiplication may be referred. 
. As in the beginning every species was 
created, the first individual of each has served 
for a model to their descendants. The body 
ef each animal or vegetable is a mould, to 



>vliich are assimilated indifferently the organic 
particles of all animals or vegetables which 
have been destroyed by death, or consumed 
by time. The brute particles, of which part 
of their composition was formed, returned to 
the common mass of inanimate matter; but 
tlie organic particles, whose existence is per- 
manent, are again resumed by organized bo- 
dies : they are extracted at first from the earth 
by vegetables, and then absorbed by animals 
wlio feed thereon ; and thus serve for the sup- 
port, growth, and expansion of both. By 
this constant and perpetual circulation from 
body to body, they serve to animate all orga- 
nized beings. These living substances ia 
quantity are always the same, and differ only 
in form and appearance. In fertile ages, and 
when population is the greatest, the whole sur- 
face of the earth seems to be covered with men, 
domestic animals, and useful plants. But in 
the times of famine and depopulation, the fe- 
rocious animals, poisonous insects, parasitical 
plants, and useless herbs, resume, in their turn, 
dominion over the earth. To man these changes 
are material, but to Nature they are perfectly 
indifferent. The silk worm so inestimable to 
the former, is to the latter only a caterpillar 
of the mulberry tree . Though this cater pillar, 


S52 BUFFO n's 

which so materially assists in the supply of our 
luxuries, should disappear; though the plants, 
from which our domestic animals procure their 
nourishment, should be devoured by other ca- 
terpillars ; though still others should destroy 
the substance of our corn before the harvest ; 
in short, though man and the larger animals 
should be starved by the inferior tribes. Na- 
ture would not be less abundant nor less alive ; 
she never protects one at the expence of ano- 
ther, but especially supports (he whole. As 
to individuals she is regardless of number ; she 
considers them only as successive images of 
the same impression ; as passing shadows of 
which the species is the substance. 

in earth, air, and water, then, there exists a 
certain quantity of organic matter which can- 
not be destroyed, but which is constantly assi- 
milated in a certain number of moulds, that arc 
perpetually undergoing destruction and re- 
newal : these moulds, or rather individuals, tho' 
varying in number in every species, are never- 
theless always the same, that is, proportioned to 
the quantity of living matter ; and this appears 
to be absolutely the case, for if there wore any 
redundance of this matter, or if it were not at 
all times fully occupied by the individuals of 



the species which exist, it would, most assur- 
edly, form itself into new species, for being 
alive it would not remain without action ; and 
once uniting with brute matter is sufficient to 
form organized bodies ; and it is by this con- 
stant combination, and invariable proportion, 
that Nature preserves her form and consistence. 
The laws of Nature, both with respect io 
the number of species and of tl>eir support and 
equilibrium, being fixed and constant, she 
would invariably have the same appearance, 
and be in all climes absolutely the same, if her 
complexion did not so completely vary in 
almost every individual form. The figure of 
each species is an impression, in which the 
principal characters are so strongly engraven as 
never to be effaced ; but the accessory parts and 
shades are so greatly varied that no two indi- 
viduals have a perfect resemblance to each 
other ; and in all species there are a number 
of varieties. The human species, which has 
such superior pretensions, varies from white to 
black,from small to great, &c. The Laplander, 
the Patagonian, the Hottentot, the European, 
the American, and the Negro, though the off- 
spring of the same parents, have by no means 
the resemblance of brothers. 
TOL, X. Z z It 

tt is evident, therefore, that every species U 
subjectfo individual difFerenccs,but thateacli! 
ofthem does not equally possess the constant 
varieties \^'hich are perpetuated fhrouj^b succes* 
si vr generations* themoredignifiedthespecies, 
the less changeable is its figure, and the less are 
the varieties of it. The multiplication of ani- 
mals being inversely in proportion to their 
magnifudc, as the possibility of variation must 
be in exact proportion to the numbers they 
produce, there consequently must be more va- 
rieties among the small than the large animals ; 
and also, for the same reason, there \>ill be a 
greater number of species which seem to ap- 
proacli each other ; for the unity of the spe- 
cies in the large animals IS more fixed, and the 
nature of their separation more extended. 
What a number of various and similar spe- 
cies surround those of the squirrel, the rat, 
and other small quadrupeds, while the massy 
elephant stands alone, without a compeer, 
and at the head of the whole. 

The brute matter, of which the body 
of the earth is principally composed, is 
a substance that has not undergone many 
alterations, thongh the whole has more 
than once been disturbed and put in mo- 



Cion by the hand of Nature. The globe of the 
eartli has been penetrated by fire, and after- 
wards covered and disordered by water. The 
sand, which occ^ipies the interior parts of th^ 
earth, is a vitrified matter ; and the layers of 
clay, by which its surface is covered, are no- 
thing but the same sand having been decora^ 
posed by tlie operation ofthe waters. Granite, 
free-stone, flint, nay, all mjetals, are compos- 
ed of this same vitrified matter, whose parti- 
cles have been condensed or sepa rated, accord^ 
ing io the laws of their affinity. These sub* 
stances are totally destitute of animation ; 
they exists and will continue to do so, inde- 
pendently of animals and vegetables. There 
are, however, many other substances, which, 
although they have the appearance of l)eing 
equally inanimate, orijrinate from organized 
bodies; and of this description are marble, 
lime-stone, chalk, and marl ; they being com5- 
posed of the fragments of shells, and of those 
small animals which by transforming the wa- 
ter of the sea into stone, produce coral, and all 
the madrepores, whose varieties are numberless, 
and whose quantity are almost immense. Pit- 
coal, turf, and many other substancts found in 
the upper strata, are also of this nature, they 
being only the residue of vegetables which 
have been wore or less corrupted or consumed. 


S55 buffon's 

Besides these, there are other substances "vihiGll 
have been produced by the second action of 
fire upon original matter ; these are but few 
in number, and consist of such as pumice* 
stones, sulphur,the scoria of iron, asbestos, and 
lava. To one or other of these three great 
combinations may be referred all the relations 
of brute matter, and all the substances of the 
mineral kingdom. 

The laws of affinity, by which the various 
particles of these different substances separate 
from each other, in order (o unite among them- 
selves and form homogeneous masses, are per- 
fectly similar to that general law by which 
the celestial bodies act upon each other; in both 
cases their exertions are the same. Globules 
of water, of sand, or of metal, have the same 
influence, and act upon each other as the earth 
acts upon the mmxi ; and if the laws of affinity 
have hitherto been deemed different from 
those of gravity, it is because the subject has 
been considered in a very confined point of 
view. The mutual action of celestial bodies iii 
very little influenced by figure; their distance 
from each other is so very great, that this is 
necessarily the case ; but when they are not fat 
asunder, then the effect of figure is considerable. 
For instance, if the earth and moon, instead 
af spherical figures, were both short cylinders, 



and exactly equal throughout in their diame"* 
ters, their reciprocal action would be very lit- 
tle varied from what it is at present, because 
the distances of all their parts irom each otlier 
would be very little changed. But it' these 
two globes were cyliiiders of great extent, 
and approached near to each otiier, the law of 
their action would seem to be dif^ 
ferent, inasmuch as the distances of their 
parts would be greatly varied ; and hence 
whenever figure becomes a principle in dis- 
tance the law will appear to vary, although in 
fact it is always the same. 

The human intellect guided by this prin- 
ciple, may advance one step further in pene- 
trating into the operations of nature. The 
figure of the constituent particles of bodies still 
remains unknown ; we cannot entertain the 
smallest doubt that water, air, earth, metals, 
and all homogeneous particles, are compo-^ed 
of elementary particles, v>hich are perfectly 
similar, although we are s'ill ignorant of their 
figure. By the aid of calculition this at pre- 
sent unknown field of knowled-^e may be dis- 
closed by {.O'-terity, and the figure of the ele- 
mentary bodies be ascertained with tolerable 
precision. They may take the principle W6 
have established as the basis of their enquiry ; 


558 buffon's 

namely, '' that all matter is attracted in the 
*' inverse raiio of ihe square of the distance ; 
^' and this law >eems to admit of no variation 
^' in I articular at(ractionsbuiTvh?it arises from 
^' the figure of the con^tiiueut particles of each 
*^ substance, because this figure enters as an 
'* element or principle into the distance ;"and 
having once discovered, by repeated experi- 
ments, the law ofattraciion in any particular 
substance, they may then, by the aid of calcu- 
lation, be able to trace the figure of its consti- 
tuent particles. To render this point more 
clear, let us suppose, that by placing mercury 
on a perfectly jjolished surface, repeated expe- 
riments prove that this fluid metal is always 
attracted in the inverse ratio of the cubeof the 
distance ; it will then become necessary to in^ 
vestigate what figure gives this expression ; 
and this figure will be certainly thatof thecon^- 
stitucnt particles of mercury. If it should ap- 
pear, by such experiments, that the attraction 
of mercury was in the inverse ratio of the 
square of tlie distance, it would be clearly de^ 
TOonstratcd that its constituent particles were 
spherical, because a sphere is the only figure 
which observes this law, and at whatever dis-r 
lance globes are placed the law of their attrac? 
tion is always the same. 


BfATUllAL lilSTTORY. 25^ 

Newton had some idea that chemical affini- 
ties (which are nothing more in fact 
particular attractions which we have men- 
tioned) were produced by the same kind of 
laws as those of gravitation; but he does not 
appear to have perceived <hat all those parti- 
cular laws were merely simple modificationg 
of the general one, and that their apparent dif- 
ference arose solely from the circumstance of 
(he figure of the atoms, which attract each 
other, having, when at small distances, a 
greater influence upon the force of this law 
than the mass of matter. 

It is, notwithstanding, upon this theory that 
the perfect knowledge of brute matter depends. 
The basis of all matter is the same, and its 
form throughout would be perfectly similar, if 
the figures of its constituent particles wer? not 
different ; and th us it is that one hoTiogeneous 
substance can differ from another only in pro- 
portion to the difference of their original par- 
ticles. A body composed of spherical particles 
ought to be one half specifically lighter than 
that whose particles are cubical, because as the 
first only touch each other by their points, 
they leave intermediale spaces equpl to what 
they occupy, whereas the cubical particles 
join without leaving the smallest interval, and 
must consequently form a matter half as heavy 


§60 BUFFOM*fi 

again. Although the figures are considerably 
varied, that varialioii is by no means so great 
as we might imagine, since Nature has fixed 
the limits of lightness and gravity. Gold and 
air, with respect to density, are the two ex* 
tremes, and therefore all the figures in Nature 
must be comprehended as coming between 
those two ; such as would have produced 
heavier or lighter substances have been re* 

In speaking of figures, as employed by Na* 
turp, I do not mean to imply that they must 
be necessarily, or are exactly, similar to those 
geometrical figures which we form in our 
imagination. We form laws by supposition) 
and then endeavour to rendpr them simple by 
abstraction. It is very possible that there are 
neither exact cubes nor perfect spheres in the 
universe; but as nothing certainly exists with*- 
out form, and as from the variation of subr 
stances the figures of the elements are differ- 
ent, some of them most undoubtedly must ap" 
proach to ihe sphere, the cube, and all the 
other regular figures which we have conceived. 
The precise, absolute, and abstract figures 
which our minds are so frequently induced to 
admit, cannot have any existence, because 
all objects are related, and differ only by al* 
most imperceptible shades. It is by the 



same ruk tbat when I speak of one substance 
as being entirely full, because composed of cu- 
bical particles, and another as being not more 
than half full, because its parts are spherical, 
I mean only comparatively, and not that such: 
substances really exist ; for experience has 
fully informed usj that in transparent bodies^ 
such as glass, which is both dense and heavy, 
there is but a small quantity of matter in pro- 
portion to the extent of the intervals ; nay, as 
we have before observed, it might be demon- 
strated that even gold, Mhich is the most dense 
species of matler, has more vacuities than 

To investigate the powers of Nature is the 
object of rational mechanics, while active me- 
chanics is solely confined to a combination of 
particular po^vers, and consequently the art of 
constructing machines. This art has at all 
times been certain of cultivation from necessity 
and convenience; and both ancients and mo- 
derns have equall}^ excelled in it. But rational 
mechanics is a- science invented in our days ; 
for, from the days of Aristotle to those of Des- 
cartes, even the philosophers have reasoned no 
better upon the nature of motion^. than uni- 
formly to mistake the effect for tlie ca\ise. Im* 
pulsion was the only force with which they 
VOL X. A a a were 

S62 BUFF0!^8 

were acquainted; to it they attributed the 
effects of others, and all the phenomena of the 
universe. If this idea of theirs had been pro- 
bable, or even possible, impulsion, which they 
regarded as the sole cause, must have been a 
general effect, which equally belonged to all 
matter, and which equally exerted itself in all 
places, and at all times ; but every day demon- 
strated the contrary to be the fact ; for they 
must have perceived that this force had no ex- 
istence in bodies at rest ; that it had but a 
short subsistence in projected bodies, being 
soon destroyed by resistance ; that a fresh im- 
pulse was absolutely necessary for its renewal, 
and that, consequently, so far from being a 
general cause, it was only a particular effect 
produced by others more general. 

It is true, however, that we ought to consi- 
der a general effect as a cause, for we cannot 
become acquainted with the real cause of thig 
effect, because all our knowledge is derived 
from comparison, and as there is not any 
thing to which we can compare an effect, 
which is supposed general, and equally belong- 
ing to every thing, we can know it only by 
the fact. According to this view, attraction, 
or gravity, being a general effect common to 
all matter, and clearly evinced by the fact, 



ought io be considered as a cause; and to 
which all particular causes should be referred, 
nay even that of impulsion, since it is less ge- 
neral and less constant ; and the principal dif- 
ficulty is to perceive how impulsion can be an 
effect of attraction ; for if we rest on the com- 
munication of motion by impulse, we are then 
persuaded that it can only be transmitted from 
one body to another by elasticity, and that all the 
hypotheses, which suppose a communication 
of motion in hard bodies, are mere ideal fan- 
cies, which do not exist in Nature. A per- 
fectly hard or a perfectly elastic body is en- 
tirely imaginary, as neither of them really eX' 
ist ; for it is certain tliat nothing exists ab- 
solutely or in extreme; and the idea ofper- 
tion must suppose one or the other. 

It is certain that if there were no elasticity 
in matter there would be no impulsive force ; 
for instance, if we throw a stone, the motion it 
acquires is communicated by the elasticity of 
the arm. When motion is communicated by 
one body in action encountering another at 
rest, how can we possibly suppose it to be done 
otherwise than by compressing the spring of 
the elastic particles it contains, which recover- 
ing itself almost immediately after, gives to the 
whole mass a force equal to that which it re- 
ceived ^ 


ceived ? How a perfectly hard body sbouid 
admit this force, or receive rootion, is beyond 
comprehension ; and the enquiry is uniaeces- 
^ary, since no such body exists ; for, all bodies 
areendwved with elasticity. The force of elec- 
tricity is proved by experiments to be elastic, 
and to belong to matters in general ; and there- 
fore, if no other eiasticity existed in the interior 
parts of bodies but that of this eJectrieal mat- 
ter, that would be sufficient for the comraunica*- 
tion of motion ; and consequently to this great 
spring, aR a general effect, the particular cause 
of impulsion must be attributed. 

A little reflection on the mechanism of elasti- 
city will convince us that its force depends on 
that of attraction. To have a still more clear 
idea of this subject, let ois suppose a spring 
the most simple, such as of a solid angle of 
iron, or of any other hard substance, and then 
see what will be the result of compressing it. 
By compression we oblige the parts adjacent 
to the top of the angle to liend, or to separate 
a little from each other ; bsit the pressure being 
removed they again approach as luear as they 
had done before. Their adhesion, from which 
the cohesion of bodies results, is clearly an ef- 
fect of their mutual attraction. Upon the 
spring beitig pressed this adhesion is nr»t de- 


stroyed, because, althoiigh the particles are 
separated, they are not removed bejoud the 
sphere of their mutual attraction; consequently 
the moment the pressure is taken away the 
force is renewed, the separated parts draw 
near, and their spring is restored. Bvit if the 
pressure be too violent, they will, in that case, 
be removed beyond the sphere of their attrac* 
tion, and the spring will break, because the 
compressing force will be greater than that of 
cohesion, or that of mutual attraction, by 
which the particles are kept together. This 
proves that elasticity can only exert itself in 
proportion to the cohesion of the particles of 
matter, tliat is^ in proportion as they are united 
by the force of their mutual attraction ; from 
which it results, that elasticity in general, 
which alone can produce impulsion, and im- 
pulsion itself, are owing to the force of attrac- 
tion, and are only particular eifects which de- 
pend on that general one. 

Notwithstanding that these ideas appear to 
be perfectly clear to me, 1 do not expect to see 
them adopted. People in general reason only 
from their sensations, and natural philosophers 
determine from their prejudices ; as, therefore, 
both these must be set aside, very few will re- 
main to form a proper judgment; but such 


B66 bufpon's natural history, 

is the dignity of Truth , that she is content 
"with a few admirers, and is always lost in a 
crowd ; she is at all times august and majestic, 
notwithstanding which she is frequently ob- 
scured by fantastic opinions, and obliterated by 
fanciful chimeras. I, however, view and un- 
derstand Nature in this manner, and am almost 
induced to believe that she is still more simple ; 
the phenomena exhibited by brute matter is 
caused by a single force, and from this force, 
combined with that of heat, originate those 
living particles which gave rise to, and sup- 
port all, the various effects of organized bo-* 


H. C. State Colkti 

T. Gillet, Crown-court, Fleet-street. 

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